To many, Cooper Manning is the "lost" Manning brother. He's the one without Super Bowl rings, Pro Bowl appearances and national television commercials. 

The Book of Manning, an ESPN film produced by the same people who brought you the 30 for 30 series, goes out of its way to dispel that notion for good. Cooper Manning, and the pivotal role he played in Eli and Peyton's life, is one of the overarching themes in film, which premiered Tuesday night on ESPN.

The older brother of Eli and Peyton, Cooper was once a football star himself. Though the 6'4" big brother didn't have the arm of his two younger siblings, he became an All-State wide receiver and was headed to Ole Miss—with many thinking he was on an NFL journey.

Cooper Manning never caught a collegiate pass.

Before his freshman season, Cooper began suffering from numbness in his hands and fingers, and had some "atrophy" in his right bicep. Archie and Cooper then flew to the Mayo Clinic, where he underwent extensive testing. The results would shape the Manning family trajectory—not only then, but serve as a fundamental event in each brother's life, particularly Peyton's. 

Cooper was diagnosed with spinal stenosis, which is a narrowing of the spinal canal. According to the Mayo Clinic, the injury places pressure on a person's spinal cord and the nerves that control movement throughout the spine. It's usually caused by what most ailments are—simple aging. The median age for the condition is 64.

Cooper was 18 at the time of his diagnosis. 

His career was over before it even began. Because of the spinal stenosis, the wrong hit could have left Cooper paralyzed or even worse. He and Archie subsequently flew back to Ole Miss, where Cooper met with teammates, who offered their undying support. 

It was at that point in the film, describing the reaction of teammates, where over two decades' worth of emotion starts bubbling out. He speaks of how the support made Archie, his former NFL-playing quarterback of a father, "proud." And, in one of director Rory Karpf's best moments in the film, Cooper opens up about what he still misses about the game. 

"I think what I miss most about football is...the guys," Cooper said. "Not winning, or losing or catching touchdowns. It was like, the locker room and the bus rides home."

Hearing Cooper break down about the injury is particularly affecting, mainly because he's been so unabashedly supportive of his brothers and seemingly happy with his lot in life.

A part owner of an energy investment firm with holdings in oil and gas companies, Cooper has a net worth of $15 million, according to Celebrity Networth, for his off-the-field exploits. He has, in many ways, the All-American life that so many dream of—wife, three kids, wealth beyond our wildest dreams.

Credit in that moment goes to Karpf, who did an outstanding job of touching on the Manning family dynamic through the 90-minute documentary. ESPN's 30 for 30 Twitter feed was covering the film as it aired live, and they revealed that Archie and Olivia Manning both openly wept upon seeing their son get so emotional:

“Historically I haven’t really talked about that a lot,” Cooper told USA Today, according to Chris Strauss, of breaking down in the film. “Rory caught me on a weak day. We had talked for a long time during that interview session and he got to me a little bit. I’ve always tried to downplay the whole surgery and injury and just wanted to get back to normal. This was the one time I guess you got the full scoop.”

Of course, Cooper's diagnosis didn't just affect him. Peyton, who shared multiple scenes with his older brother via old home movies in Book of Manning, was particularly heartbroken. The Denver Broncos quarterback was Cooper's signal-caller in high school, tossing him touchdowns as, undoubtedly, Mississippi's best brother-to-brother tandem.

When the diagnosis came down, Cooper gave Peyton a letter, which stated he wanted to live the football career he couldn't have through his younger brother. Via Sports Illustrated:

I would like to live my dream of playing football through you. Although I cannot play anymore, I know I can still get the same feeling out of watching my little brother do what he does best. I know now that we are good for each other, because I need you to be serious and look at things from a different perspective.

I am good for you, as well, to take things light. I love you, Peyt, and only great things lay ahead for you. Thanks for everything on and off the field.

Suffice it to say, Cooper picked a pretty good surrogate NFL career. Peyton, unquestionably a future Hall of Famer, saw this film air just one day after he broke the record for most touchdown passes through three weeks with 12. 

But more than on the field, Cooper Manning has provided Peyton with inspiration. Just two years ago, Peyton's own career was in jeopardy after multiple neck surgeries cost him the 2011 season and his starting job with the Indianapolis Colts. During that time, Cooper sometimes worked as a consigliere for Peyton and the media, offering supportive words about his brother's comeback. 

Cooper could never make a comeback, but Peyton did. He nearly won an MVP award last season in his first with Denver and is the unquestioned favorite to win it through the first three weeks this year.

Two weeks ago, Peyton's aerial assault on the NFL rampaged through Eli's New York Giants. Although Eli threw for 362 yards, it was Peyton's Broncos who dropped 41 points en route to a blowout win.

Cooper wasn't in the audience. He attended the first Manning Bowl and decided that was enough. But the spirit of Cooper Manning—and the two brothers who always play in his honor—was there. It always is. Because if you learn anything from The Book of Manning, it's that no matter how dire things get, family will always be there to make it just a little bit better.