That Zelig-like identity rested largely on a series of seven books in which the New York–born, Harvard-educated Plimpton threw himself both physically and intellectually into the professional sporting life. Decades before the onset of reality TV and the Twittersphere, Plimpton starred in his own Everyman story. And this year Little, Brown is reissuing all seven stories on the 50th anniversary of the most famous of the series, Paper Lion: Confessions of a Last-String Quarterback.

Along with Paper Lion are books—and enhanced e-book versions—on Plimpton’s experiences with baseball (One for the Record and Out of My League), hockey (Open Net), golf (The Bogey Man), boxing (Shadow Box), and football (Mad Ducks and Bears). With introductions by Mike Lupica, Bob Costas, Denis Leary, Jane Leavy, and Steve Almond, this series will introduce the erudite enthusiasms of Plimpton to a new generation of readers and sports fans.

Paper Lion, like the other sports books, came out of articles he wrote for Sports Illustrated, and here Plimpton, after approaching several football teams, convinces the Detroit Lions to take him on. He describes showing up at the private-school campus where the Lions are training. The 36-year-old writer pulls into the driveway of a boys’ boarding school called Cranbrook in a rented convertible. At the registration desk he is mistaken for a member of the other group dorming there—Episcopalian bishops, in town for a convention.

“There are people who would perhaps call me a dilettante,” Plimpton once said, “because it looks like I’m having too much fun. I have never been convinced there’s anything inherently wrong in having fun.”

What resulted from his fun was a first-hand account of what happened on the line of scrimmage—a view that fans were not otherwise afforded at the time.

“Plimpton wrote Paper Lion,” Nicholas Dawidoff says in the book’s introduction, “in what was still a Walter Mitty era of armchair fandom when from the bleachers all reveries were plausible.” The private-school setting of Paper Lion, according to Dawidoff, highlighted “that central juxtaposition of an amateur among professionals, elitist intellectual amid hard-hat muscle.”

Plimpton’s second wife, Sarah Dudley Plimpton, to whom he had been married 12 years when he died in 2003, recently showed me around the same Upper East Side town house where Plimpton lived since the 1950s, when he was renting an apartment in the building. It was there, with views of the East River, where Plimpton threw his famous parties for the Paris Review. Sarah directed me to a room with a desk and lined with bookshelves. Most everything had been filed and collected in plastic bins—his boxing gloves, the red leather faded and cracked; the robe that Ali wore, which, though his name is stenciled on it, actually feels like it had been taken from a Holiday Inn; Plimpton’s football cleats, which had been bronzed; his chair, wood with worn leather. She showed me the Toots Shor menu with the Ali-Moore poem.

Sarah Plimpton reached for one of the plastic bins on the shelves labeled “Paper Lion”—notebooks, a letter from Jack Mara, former president of the New York Giants, politely denying Plimpton’s request to train with the team, and photos. There is one of Plimpton stretching out on the practice field. He’s long and lanky, and showing a bright smile to the camera—obviously having fun. The photo has long been fused to the glass, though the frame is gone. The photo, she explained, was recovered from a Dumpster. “The co-op was cleaning out the basement,” said Sarah Plimpton. “I thought I better look and see what they’re throwing in there.” She also retrieved videos of interviews and movies that would later be used in Plimpton! Starring George Plimpton as Himself, a 2014 PBS American Masters documentary, as well as in Little, Brown’s trailer to the book series.