Seen the movie? You still need to read the book.

If the PBS Frontline documentary "League of Denial" is a damning indictment of the National Football League's action -- and inaction -- on the problem of brain damage in football, the book of the same name is a sweeping conviction. In copious, eye-opening detail, authors Steve Fainaru and Mark Fainaru-Wada lay out the past and present case against the league -- and the troubling implications for sports, society and public health going forward.

Herein, six in-depth takeaways:

1. The denial started early

At its core, "League of Denial" is a story about self-serving bulls--t: the National Football League created a bulls--t committee which produced bulls--t research supporting bulls--t medical practices, all in service of the bulls--t (but profitable!) notion that unlike boxing and military combat and automobile accidents and pretty much every other kind of activity that involves getting hit in the head, getting hit in the head while wearing a football helmet does not produce brain damage.

As the book makes clear, the bulls--t was there from the beginning.

In the documentary film, the NFL's scientific book-cooking and data cherry-picking seems to take off in 2004, when the league's since-discredited Mild Traumatic Brain Injury Committee published the first of a series of since-discredited papers proclaiming things like: (a) concussions in professional football "are not serious injuries"; (b) that "many [concussed] players can be safely allowed to return to play on the day of injury," which also might hold true for college and high school athletes; (c) that "professional football players do not sustain frequent repetitive blows to the brain on a regular basis."

(Note: the latter assertion is not only redundant and weasel word-y, but also patently absurd. Here's how the authors of "League of Denial" describe former Pittsburgh Steelers center Mike Webster's play on the line of scrimmage, which wasn't exactly unique when it comes to blocking and tackling in football: "You gotta see this Webster," Dick Haley, the [Steelers'] director of player personnel, told [team owner Art] Rooney. "He hits like Rocky Marciano." Webster's technique seemed flawless: He had a knack for smashing his head like a sledgehammer underneath an opposing lineman's chin, then controlling the bigger man by using his leverage.")

In the book, by contrast, the league's funny numbers predate the MTBI committee, which was created by then-league commissioner Paul Tagliabue in 1995. Following a series of concussions during the 1994 season to high-profile players including Dallas Cowboys quarterback Troy Aikman, the NFL claimed it had been tracking concussions since 1989 -- and according to a league spokesman, the rate of brain injury was constant: only one concussion per every three or four games. "In the big picture, when you consider the number of times the head is impacted, the number of concussions is relatively small," said league spokesman Greg Aiello at the time. "But hey, they do occur. And maybe there's more we can do."

But hey! Beyond flippancy, there was a problem with the NFL's cavalier, nothing-to-see-here, please-disperse attitude regarding brain damage. It was rooted in bad math. As "League of Denial" explains:

… the league, Aiello acknowledged, was counting head injuries as concussions only when a player lost consciousness or was seriously dazed. Garden-variety concussions were not part of the program. [Pittsburgh Steelers brain doctor] Joe Maroon did his own calculations and estimated that two to four concussions occurred in every NFL game. (Bold added).
That discrepancy perhaps should have raised red flags. At minimum, there was a 156 percent difference between the rate of concussions reported by the NFL and the rate reported by the senior neurological expert in the league. Maroon said that he, for one, was quite concerned. But few people seemed to notice …

From there, the NFL's problem with noticing and acknowledging brain damage -- at least publicly -- only grew more pronounced.

2. NFL doctors said one thing in public … and another in private

Over eight NFL seasons, former New York Jets receiver Al Toon may have suffered as many as 10 concussions. Following his final brain injury, he consulted with an area neurologist named Ira Casson. Casson previously had examined scans of Muhammad Ali's brain for Sports Illustrated and determined that the boxer had brain damage even before he quit the sport.

According to "League of Denial," that wasn't Casson's first experience with brain damage caused by concussions and blows to the head:

… a decade earlier, Casson had led a landmark study that examined 10 boxers who had been knocked out. He discovered cerebral atrophy in half of them, an indication of chronic brain damage. Toon already had decided to put his fate in the hands of his doctors, and Casson, for one, had grave doubts: "I'm not sure that you should do this anymore," the neurologist told Toon. "I don't know what the next concussion is going to do to you." Toon interpreted this to mean that he might never wake up …

In other words, Casson suggested that the 29-year-old Toon retire from football, a sport that involves getting hit in the head, or else suffer an indeterminate -- but increased and very real -- risk of devastating long-term brain damage. This happened in 1992. Fifteen years later, the same Casson served as the co-chairman of the NFL's concussion committee. Totally coincidentally, he had an astonishing change of heart, engaging in the following on-air conversation with reporter Bernard Goldberg during a 2007 episode of HBO's "Real Sports":

Goldberg: Is there any evidence, as far as you're concerned, that links multiple head injuries among pro football players with depression?

Casson: No.

Goldberg: With dementia?

Casson: No.

Goldberg: With early onset of Alzheimer's?

Casson: No.

Goldberg: Is there any evidence as of today that links multiple head injuries with any long-term problem like that?

Casson: In NFL players?

Goldberg: Yeah.

Casson: No.

Throughout the pages of "League of Denial," a pattern emerges: NFL-affiliated doctors privately counseling players with multiple concussions and unresolved medical symptoms to retire, the better to reduce their risk of additional and permanent brain damage. Publicly, however, those same doctors repeatedly deny a link between football and long-term cognitive harm -- even as a growing body of outside evidence supports their actions to the contrary.

Consider the case of Merril Hoge. In 1994, Hoge suffered a severe concussion during a preseason game. He sat out for a week, then played in four consecutive games. In his next game, he was knocked unconscious, hit so hard in the head that his facemask caved in. He entered a mental Twilight Zone. Hoge couldn't remember his daughter's name, who the president was, why he was in the hospital. He ultimately was examined by Maroon, whose first thought was, "I don't want anybody to die following a football game on my watch."

Maroon told Hoge to quit the sport. Hoge agreed. At least at first:

… Over the next several months, as Hoge's memory slowly returned, Maroon would get phone calls in the middle of the night. He knew who it was before he answered. "Hey, you know, Doc, I feel great!" Hoge would say. "There's nothing wrong with me!"

Maroon would patiently walk Hoge through it all over again. There was no telling what might happen if he got hit again. He could lose his memory permanently, even his life. And there was always the chance that he would accelerate the process that led to a series of devastating diseases: Parkinson's, Alzheimer's, dementia …

Parkinson's. Alzheimer's. Dementia. Three of the horrific degenerative neurological diseases the NFL spent almost all of the 2000s denying had any link to football. Of course, it's not as though Maroon -- the Steelers' long-time brain specialist and a member of the MTBI committee -- did a whole lot to set the league straight. Five years after he told Hoge to retire and stay retired, Maroon publicly cast doubt on claims by Webster and his doctors that the blows to the head he endured during his Hall of Fame football career had left him with permanent brain damage. Similarly, Maroon called a 2005 diagnosis of football-induced chronic traumatic encephalopathy in former Steelers lineman Terry Long "preposterous and a misinterpretation of facts."

Then there's Mark Lovell. A Steelers neuropsychologist, MTBI committee member and colleague of Maroon, he helped develop early tests designed to help gauge concussion severity among football players. He also co-authored committee papers concluding that concussions are minor injuries; nearly all NFL players recover quickly and completely; neuropsychological testing is almost useless in assessing football-caused concussions; football doesn't cause brain damage, ever. In the book, the Fainaru brothers question Lovell about the NFL work bearing his name -- papers that not only contradicted his professional speciality and public statements, but also several non-public cases in which a league-run disability board had awarded former players benefits for football-induced brain damage:

Neuropsychology was of limited use in diagnosing concussions?

"Obviously, I didn't write that," Lovell said.

Multiple concussions do not increase the risk of further injury?

"I didn't write that."

NFL players don't get brain damage?

"I didn't write that," Lovell said again …

"Could I have said, you know, 'God dammit!'" said Lovell. "Probably. Didn't."

Why the public denial and private acceptance? The medical equivalent of touting the joys of football but refusing to let your own children play? Perhaps because public denial was the official NFL company line, dating back to Tagliabue's 1994 proclamation that brain damage in the sport was merely a figment of the media's imagination, a "pack journalism issue." And perhaps because public denial let the league and its doctors off the hook -- or at least gave them a stronger argument against legal liability -- when it came to mismanaging the health of the players under their care. After all: Maroon was Long's doctor. Webster's, too. According to the league's own published data, pretty much every league team and doctor allowed concussed athletes to return to play in the same game. Admitting that was a bad idea -- admitting a link between football and battered brains -- would mean admitting some level of responsibility for the damage done. And that, in turn, could cost a fortune in subsequent lawsuits, plus diminish football's cultural standing as a more wholesome, less dangerous, still-violent alternative to bloodsports such as boxing.

Oh, and don't assume that this pattern has entirely changed. According to the book, NFL team doctor David Chao and affiliated scientist Kevin Guskiewicz last year helped direct the brain of former linebacker Junior Seau to the National Institutes of Health and away from researchers in Boston and California who previously had been critical of the league --even smearing the man who discovered CTE, Bennet Omalu, in the process. The NIH's chief of surgical neurology? Russ Lonser. Who also happens to be the head of research of the league's current concussion committee.

Last January, the NIH and three independent neuropathologists concluded that Seau had CTE. In "League of Denial," Gina Seau says her family was told by Lonser that her ex-husband had gotten the disease from a "lot of head-to-head collisions over the course of 20 years of playing in the NFL. And that it gradually, you know, developed the deterioration of his brain and his ability to think logically." Publicly, however, Lonser and other officials have refused to speculate on the cause of Seau's brain damage. And two months after the NIH received Seau's brain, the NFL donated $30 million to the institutes for concussion research, the largest charitable gift in the league's history.

Coincidence?

3. NFL medicine is structurally -- and hopelessly -- conflicted

Before Omalu examined Webster's brain and discovered the first case of CTE in a former football player, University of Pittsburgh Medical Center forensic psychiatrist Jonathan Himmelhoch diagnosed the living Webster with chronic brain damage. Truth be told, the diagnosis wasn't exactly rocket science. Webster was slowly slipping into madness. He could barely function without constant doses of Ritalin, a psychostimulant generally used to treat attention deficit disorder. Near the end of his life, he was homeless, using super glue to patch his wounds and fix his deteriorating teeth. He even Tasered himself to fall asleep.

Himmelhoch examined Webster six times over a three-month period and concluded that his condition was caused by "multiple blows while playing center in the NFL." In a six-page report, Himmelhoch also concluded that:

part of Webster's desperate condition derived from the fact that his medical treatment had been compromised from the start of his career. His care, he wrote, "has been delivered by doctors working for two masters -- 1st the Pittsburgh Steelers and second, Michael L. Webster." Those doctors repeatedly allowed or encouraged Webster to play hurt, essentially refusing to save him from himself to advance the interests of the team.

"Full recovery of subtle head injury is a necessity before resuming any job," Himmelhoch wrote. "If there is no recovery period, subtle, then manifest cortical injury is insured. One can conclude, therefore, to reasonable medical certainty that Mr. Webster's progressive deteriorating encephalopathy began while he was still playing NFL football" …

Football can cause brain damage. But lousy, inadequate, compromised medical care can make that brain damage much worse. And that's what the NFL provided. Maybe still provides. Above all else, "League of Denial" paints a picture of league medicine as hopelessly conflicted, serving two masters that are usually at odds -- the first, player health and well-being; the second, playing time and profits -- and almost always prioritizing the latter over the former.

Athletes are incentivized to play with -- and through -- injuries. Even brain injuries. Otherwise, they get cut. Team doctors -- many of whom pay for the marketing privilege of affiliating with a pro team -- are incentivized to let them. League-affiliated researchers are incentivized to downplay and dismiss the risk of brain damage, lest they lose their affiliation and concurrent funding. The NFL itself shares a similar incentive, not to mention the team owners and liability lawyers who run it. The league is basically a highly successful company town, populated by company doctors and company men. In the short term, no one wants to lose money, status or prestige; in the long term, no one wants to see football lose the same.

All of this is hell on the Hippocratic oath.

When Tagliabue formed his concussion committee, he picked then-New York Jets team doctor Elliot Pellman to run it. Pellman specialized in joint injuries. Shoulders and knees. He was not, you know, a neurologist. He also was Tagliabue's personal physician. Which is certainly not a conflict of interest. Moreover, the book reports that the committee was "made up almost entirely of NFL insiders. Nearly half the members were team doctors, the same men who had been sending players back on the field for years. There were two trainers, a consulting engineer, and an equipment manager."

An equipment manager. Was a cheerleading choreographer not available?

Upton Sinclair once said that "it is difficult to get a man to understand something when his salary depends upon his not understanding it." That sentiment informs every page of "League of Denial." When agent Leigh Steinberg tries to alert players and owners alike to the dangers of concussions, quarterback and client Warren Moon tells him "you're probably right, but I wish you'd shut up." The editor of the neurology journal that published the NFL committee's bogus articles, Michael Apuzzo, comes across as "something of a jock sniffer," enamored with his part-time job as a neurological consultant to the New York Giants and happy to brag about his lunches with Tagliabue. NFL-affiliated doctor Mickey Collins admits that a study he co-authored concluding that a football helmet produced by exclusive league partner Riddell reduced concussion risk had "serious flaws." However, he and Lovell received $75,000 from Riddell to work on the study. As Collins tells the authors, "I needed money to fund my salary. I was going to get my ass fired, you know? So I'm looking for any kind of funding to do this research. Any struggling academic is looking for that."

Maroon, Collins and Lovell also found ImPACT, a neuropsychological testing program that becomes highly profitable thanks to its association with the NFL --even though other scientists question its efficacy, and a study of every published study on ImPACT found that the test has false positive rate of 30 to 40 percent. Which means that when the test was administered to people who haven't suffered concussions, it was picking up concussion symptoms in almost half of them.

For his part, Guskiewicz goes from being a NFL outsider and harsh critic of the league's denial to a member of its revamped concussion committee -- and someone who now criticizes research linking football to neurodegenerative disease using the same arguments the NFL once used against his own research making the same link. He tells the book's authors that he doesn't "want people to think that I was bought," yet also admits when he needs "big dollars" for football collision research, he goes to NFL executive Jeff Pash and says "Jeff, we need to buy six new systems, and it's going to cost $250,000 to install; can you authorize the purchase? And Jeff then does that."

In late 2008, the NFL asked a leading Alzheimer's researcher, Peter Davies, to examine Omalu's CTE research. The same research league scientists had been attacking and dismissing. Davies agreed. According to the Fainaru brothers, Casson then offered to pay him for his work:

… Davies declined. He wanted to avoid even the appearance of a conflict. "If you want my opinion, you'll get what I think, not what you pay for," he told Casson …

If league medicine worked the same way, "League of Denial" would be a very different book. And people like Webster might have enjoyed very different health outcomes.

4. League-affiliated and sponsored science deserves extra skepticism and scrutiny going forward

As "League of Denial" notes, the NFL is now spending tens of millions of dollars to become "the main sponsor of research that holds the potential of its own undoing." Moreover, former dissenters such as Guskiewicz and independent scientists like brain surgeon Richard Ellenbogen now staff league-sponsored player health and safety committees. Much has changed.

Or has it?

Pellman remains a league medical advisor. According to the book, Guskiewicz even sends him breakfast receipts. "He does it really well," Guskiewicz tells the Fainaru brothers. "I have to tell you, if only the university could reimburse me as quickly as he does; it's usually within minutes and the check's in the mail. But I know, it's comical." Goodell personally recruited Ellenbogen to replace Pellman and Casson as co-chair of the league's new-and-improved concussion committee. Ellenbogen has professed publicly that he knows very little about the bad old days -- but in a review of a Pellman-authored paper from the previous committee, he wrote that "the NFL MTBI committee are to be congratulated on the 14th contribution in a superb series of the analysis of concussions in NFL players." Ack. The book also states that:

… the NFL insisted that its new concussion committee - like its old concussion committee - was totally independent, yet the league monitored interviews and filtered communications with the media. Guskiewicz and his colleagues reported directly to Goodell …

Look: credible organizations such as the NIH are not as easily manipulated as, say, a group of league-dependent doctors. In addition, NFL funding doesn't necessarily taint everything it touches. That said, independent entities generally don't require (or accept) message oversight. And the league itself does not spend money haphazardly. In fact, whenever possible, it prefers to spend other people's money. (Especially yours. See stadium subsidies). What exactly is the NFL getting in return for its investment in brain damage research? Is the past prologue?

5. The NFL was -- and is -- fighting a ferocious, long-term, multi-faceted legal and public relations war

Speaking of research funding: "League of Denial" reports that in 1996, the NFL awarded a $134,000 grant to Philadelphia Eagles team doctor and Thomas Jefferson University professor John McShane to study changes in the brain chemistry of concussed NFL players. Before the study could begin, the Eagles sold their medical rights to another health care provider. McShane was out. The project was scrapped. Pellman even tried to recover some of the grant money.

Fast forward to 2000. Hoge was suing the Chicago Bears and team doctor John Munsell for mismanaging his concussion and negligently allowing him back onto the field. McShane was set to testify in support of Hoge. An NFL lawyer sent documents from the McShane-Pellman grant money dispute to Munsell's attorney, who then attempted to use them in court against McShane:

… McShane, sitting in the back of the courtroom as he watched the argument unfold, was baffled and angry … he was under attack by the league because he planned to testify on behalf of Hoge. "I couldn't understand why anybody would be mad at me," he said. "I had good intentions; I wanted to do a study that would provide valuable information. Then this change happened that I had no control over, and they were impugning me. I was just stunned" …

You are the NFL. You work with some of the best corporate defense attorneys and crisis managers in the world -- including your former commissioner, Tagliabue, who serves as a senior counsel for longtime league law firm Covington & Burling, a legal juggernaut that was intimately involved in Big Tobacco's decades-long practice of buying scientists to produce bogus work obscuring the dangers of cigarette smoke. You suspect a class action concussion lawsuit is coming. Now you're actually facing said lawsuit. How do you make sure top scientists can't testify against you as expert witnesses?

Easy. Give them money. For research. For whatever. Create a conflict of interest. Create the appearance of a conflict of interest. Muddy the waters. The NFL made a $1 million donation to a CTE research group at Boston University, a group containing of some the loudest football brain damage dissenters. The league stocked its new concussion committee with better-respected, non-affiliated experts. It made critic and pioneering sports concussion researcher Robert Cantu a senior advisor to said committee:

… At the same time, [Cantu] dispensed paid advice to the lawyers suing the league during a February 2012 strategy session in Philadelphia. When the NFL found out about his appearance, league officials sent a warning letter to the lawyers to stay away from Cantu because he worked for them. After discovering Cantu's conflicting roles, the lawyers for the players decided he was tainted as an expert witness and backed away …

Jeff Miller is the NFL's top Washington lobbyist. In 2009, Congress held hearings on football and brain damage. Capitol Hill staffers wanted to place Goodell on the same panel as the father of a boy who had died after suffering a concussion playing high school football. According to "League of Denial," Miller was apoplectic. He didn't want that visual. The league didn't want that visual. Bad, bad optics. The staffers backed down. As Maroon told Omalu in the book: if only 10 percent of mothers in America begin to conceive of football as a dangerous game, that is the end of football.

Today, Miller has a new title: NFL senior director of health and safety policy. He recently penned a newspaper editorial touting the league's "responsibility for improving youth football and making our game -- and all youth sports -- safer for the kids who play them." Part of that responsibility, the book notes, involves "reaching out to a new constituency: mommy bloggers." In the summer of 2012, the NFL hosted a luncheon at its New York headquarters. About 50 mommy bloggers were invited:

… Goodell spoke to the group about the need to change the culture of football. It wasn't totally clear to [mother and WorkingMother.com blog author Lorraine] Esposito what that meant, but she found Goodell to be solicitous, a good listener.

"To his credit, he really wanted to know," Esposito said. "I asked him to help me define what this cultural change really is. We started talking about the training and equipment. I said, 'That's not what I mean. What's the culture you're talking about?' He said: 'That is a great question, but I don't have an answer for you.'"

Still, Esposito came away convinced that the NFL was committed to creating a healthier and safer sport …

"League of Denial" reports that the luncheon included the executive director of the NFL's youth football arm, the wife of a former NFL quarterback and neuropsychologist who works with the Chicago Bears. Cantu -- who recently wrote a book stating that children under 14 shouldn't play collision sports, period -- was not invited. Nor was mention made of a memo written by a bioengineering firm contracted to help the NFL conduct a league-wide epidemiological study of concussions during the 1990s:

"A major obstacle to head injury research is the unavailability of willing test subjects," said the memo. "The NFL has graciously sponsored a research program offering its players as those living subjects."

Living subjects. Probably not a term you'll find bandied about at the next NFL mommy blogger summit.

6. The more things change …

James Vodvarka was livid. Disillusioned, too. He was a Steelers fan. A football fan. He also was Webster's personal physician. He watched Webster struggle and decline, and then watched the NFL's retirement board determine -- contrary to the professional opinions of five different doctors -- that Webster only became disabled years after leaving football, which the book notes was "a hairsplitting -- but life-changing -- distinction. It was the difference between $42,000 a year and hundreds of thousands."

Vodvarka knew this was, in a word, bulls--t. The money, of course. But also, quite possibly, the distinction. After 15 years with the Steelers, Webster played two more seasons with the Kansas City Chiefs. He retired in 1990. His family had noticed uncharacteristic changes in him as his career wound down: a short temper, a lack of focus, erratic thoughts and behavior.

In 1994, the Chiefs hired Webster as a strength coach. "League of Denial" reports that for "much of the season, Webster lived in a storage closet above the weight room at Arrowhead Stadium." His presence with the team was sporadic. Coach Marty Schottenheimer would later forget that Webster had even been part of the club.

Vodvarka wrote a letter to Webster's lawyer, Bob Fitzsimmons:

"I am and could only be appalled," Vodvarka wrote Fitzsimmons. "We are dealing with a unique situation where a human being has lost his well-deserved dignity, respected reputation and most importantly his family. The Pittsburgh Steelers and the National Football League have turned their backs, and have done nothing but try to destroy one of their most prolific players. I can only imagine what misery some of the National Football League's lesser players must suffer. Are they [the NFL] afraid to set a precedent? Do they expect the common people/taxpayers to fund their casualties while paying to watch them occur?"

Do they? "League of Denial" notes that the NFL has mounted a fierce lobbying campaign to change a provision in California worker's compensation law allowing former players who played even one game in the state to file a claim against their former team. (On the same day "League of Denial" premiered on PBS earlier this month, the NFL's campaign succeeded, potentially saving the league millions in brain damage-related claims). A proposed $765 million settlement of the concussion lawsuits has been criticized -- including by yours truly -- for being financially inadequate and also for allowing the league to walk away without admitting fault nor disclosing the full extent of what it knew and when it knew it.

Why does that matter? In 2009, a league spokesman told the New York Times that it was "quite obvious" that concussions -- including the kind you can get while wearing a football helmet -- can lead to long-term problems. That was then. Late last year, Goodell gave a speech at Harvard University's School of Public Health, described in the book as follows:

… the commissioner emphasized the need to rely on "science and facts, not speculation." He cited a recent study by the National Institute for Occupational Safety and Health (NIOSH) debunking the myth that NFL players had shorter life spans than the general population. He did not, however, note another NIOSH study suggesting that NFL players were four times more likely to develop Alzheimer's or Lou Gehrig's disease.

As he ended his day at Harvard, Goodell took a few questions from the media before being whisked away.

"Is the league's position clear that football has the potential to cause long-term brain damage?" he was asked.

The commissioner hit replay: "What we are doing is making sure that we do everything to make sure that the game is safe. Those conclusions have to be drawn by the medical community."

The denial continues.