As a sportsman, Jim Bouton was best-known as a pitcher for three early-1960s New York Yankees teams that reached the World Series.

As a careful observer and serial pot-stirrer, he was best-known for the diary he kept of the 1969 Seattle Pilots season, which led to the 1970 book Ball Four.

It was an endeavor that drew back a curtain of self-censorship that for decades obscured how Major League Baseball players lived, outside the lines, and hammered home to fans how little we really knew about them.

What we didn’t know made for a long list: How players spoke, how they interacted. How they were exploited by clubs who underpaid them and essentially owned them due to the Reserve Clause. How they went boozing at nights and pepped themselves up before games with stimulants known as “greenies”.

How they spent their free time in dissolute pursuits up to and including attempts to peer up the dresses of women during ballgames or even from hotel rooftops, with the aid of binoculars.

And for some of us who were high school juniors, the book was like a little bomb going off inside our heads. “Those guys do all that?”

On a wider level, “Ball Four” was important because it came at a time when baseball was entering a new era, one in which the players would organize to take on, collectively, the owners in a fair fight, one that yielded contracts worth millions — when in 1969 the basic one-year contract was $7,000.

Bouton died last month at age 80, and for those of us who can remember their lives as fans before and after “Ball Four”, it marks an end of innocence — or perhaps an end to the lying. Some of it, anyway.

Bouton was urged by a friend at a New York publishing house to do a semi-no-holds-barred diary of the 1969 season, most of which Bouton spent with the expansion Seattle Pilots, a team doomed to a single season in the Pacific Northwest before jumping to Milwaukee and becoming the Brewers.

Bouton made the team as a free agent, thanks to his on-again/off-again best friend, the knuckleball, a soft-toss buddy for pitchers whose arms had broken down from overuse but were not ready to give up careers. The knuckler is practically its own character in the book, as Bouton carefully chronicles each outing, always keen to make the dancing pitch good enough to get him back into a starting rotation.

I bought the book in 1970, and I bought it again last month, rereading it for the first time in a half-century.

Some of the bits that stick out:

–It was a bad time to get injured, especially for pitchers. The “Tommy John” surgical procedure for replacing an elbow tendon was a decade away; no one was talking at all about the repair of shoulder injuries. Pitchers misled clubs as long as they could when they had muscle or tendon tears that meant agony and decreased velocity on every pitch. Bouton was released by the Yankees after they rode him hard for two seasons, 1963 and 1964, and his arm went bad.

–Players had very little control of their professional lives. Once a year, a moment came when they had some leverage — agreeing on a contract for the coming season. Baseball executives made a point of limiting how much the club paid out, and had the upper hand thereafter — able to trade or release players at their whim. Also, there are several interludes pertaining to clubs arguing with players over small amounts of money, or clubs charging for soft drinks from a machine in the clubhouse.

–Commissioner Bowie Kuhn was incensed at the information in “Ball Four” and insisted Bouton recant the whole of it, according to the author. He did not. Baseball seemed most concerned with two particular anecdotes, neither of which is told at great length. One is a pinch-hit appearance in a day game by a badly hungover Yankees star Mickey Mantle, who hits a home run and gets to the dugout and says something like “fans will never have any idea how hard that was.” Also, Whitey Ford, Yankees ace during the period, had numerous illegal methods for gouging a ball to make it move unpredictably, and Bouton outlines several of them.

–Jackie Robinson broke the color line in 1947, when he joined the Dodgers, but things were a little tense, still, in 1969. Bouton rarely interacts, in his book, with the handful of black players on the Pilots roster, though he does mention at least three times that teammate Tommy Davis, a former Dodgers outfielder “was a friend” of his. Bouton roomed with white players, and if his book is any indication, almost all conversations he found interesting did not include black players. The impression created, 50 years later, is that Bouton did not quite know how to reach out to black players — and he also feared the reaction of a majority white team if he began spending off-the-field time with black players. Assuming he would have been welcome.

–The absence of advanced metrics. It was still the era of ERA, batting averages and pitcher “wins”. Bouton is obsessed by wins and rues that he has only two of them in the season. Meantime, when he wants to convey how strong an opposition team was, he recites batting averages.

–He feels it necessary to keep track of his own statistics, so he can present them to the dunderheaded manager (Joe Schultz) and pitching coach (Sal Maglie). Meanwhile, they seemed to think Bouton was a troublemaker, and they seem to bear out Bouton’s belief that they didn’t really want a knuckball pitcher on their team.

–Bouton does some self-censoring. Ballplayers are notorious for out-of-marriage sexual encounters, but Bouton stays away from the topic. The reader’s sense is that that would have crossed a line. He also avoids the use of recreational drugs, from marijuana on up, despite the linkage between the late 1960s and illicit drug usage.

There is more. Much more. It is not a short book, and the current Kindle version includes a 10-year update detailing the reaction he encountered from the baseball world. During most of that time Bouton was a sportscaster for a New York television station, which he found was no more thorough or intelligent as the baseball hierarchy.

Bouton was not officially banned from baseball, after his book came out, but he said he was rarely invited to official baseball events, including old-timer days. It is not quite accurate to say his revelations cost him years off his career, but it certainly did not help.

I recommend “Ball Four” to anyone interested in baseball history, particularly of the off-the-field variety, and in Bouton’s sketches of desperate players anxious to add another season or two to their careers. Like the author himself.