Jim Brosnan as a pitcher for the Cincinnati Reds in 1962. His books “The Long Season” and “Pennant Race” were the first inside look at baseball written by a player. (1962 File Photo)

Jim Brosnan, who helped pitch the Cincinnati Reds to the National League championship in 1961 but was better known for two revelatory books, “The Long Season” and “Pennant Race,” that were the first inside accounts of a baseball team written from a player’s perspective, died June 28 at a hospice in Park Ridge, Ill. He was 84.

He was recovering from a stroke when he developed a sepsis infection, said his son, Tim Brosnan.

Mr. Brosnan was a lanky, 6-foot-4 right-hander who had a middling career as a pitcher with the Chicago Cubs and St. Louis Cardinals before he was traded to the Reds midway through the 1959 season. He then blossomed into a standout reliever on Cincinnati’s pennant-winning team.

In some respects, however, Mr. Brosnan was a bit of an oddity in baseball clubhouses of the 1950s and 1960s. Nicknamed “Professor” because he wore glasses, smoked a pipe and read books, he stuffed magazines in his uniform to pass time in the bullpen and kept a diary of his life in baseball.

On the mound, he sometimes shouted at opposing hitters in French: “Ils ne passeront pas,” a World War I battle cry meaning “They shall not pass.”

Mr. Brosnan began publishing articles in Sports Illustrated in 1958 before signing a contract for a book about a year in the life of a ballplayer. He wrote it himself, without resorting to a ghost writer, and “The Long Season” appeared in 1960.

Nothing like it had been seen before. The book, chronicling the 1959 season, combined humor, self-doubt and unvarnished truths about ballplayers’ lives. It opened the locker-room doors to reveal the warmth, anger, ignorance and sensitivity of baseball players in fresh, surprising ways.

“The Long Season” touched on subjects few people in baseball had discussed openly before: racial awareness, boredom, fatigue, skirt-chasing by players — and the constant physical and mental struggle to maintain a spot on a major league roster.

Pulitzer Prize-winning sports columnist Red Smith praised Mr. Brosnan for writing “a cocky book, caustic and candid and, in a way, courageous.”

Among other things, Mr. Brosnan recorded his own response to being traded for the second time in two years: “I sat back on the couch, half-breathing as I waited for indignation to flush good red blood to my head. Nothing happened. I took a deep breath, then exhaled slowly. It’s true. The second time you’re sold you don’t feel a thing.”

Mr. Brosnan described players’ sexual encounters as “strenuous exercise” and portrayed a culture in which many players — himself included — drank heavily after games.

He named the players and managers he admired and, on rare occasions, skewered the ones he disliked. He acidly sketched his onetime nemesis, St. Louis Manager Solly Hemus, arguing with umpire Stan Landes: “Hemus rushed out to the plate, squeaking additional protests, pushing his nose up to Landes’s chest, like a mouse berating an elephant.”

“The Long Season” was a bestseller and soon regarded as a classic of baseball literature.

In 2002, Sports Illustrated named it the 19th-best sports book of all time. It became the model for many other first-person sports memoirs, including “Veeck as in Wreck” (1962), by iconoclastic baseball team owner Bill Veeck; Jim Bouton’s raw and raunchy inside look at baseball, “Ball Four” (1970); and “Instant Replay,” football player Jerry Kramer’s 1968 book about a season with the Green Bay Packers (written with sportswriter Dick Schaap).

“ ‘The Long Season’ not merely changed everything,” Washington Post book critic Jonathan Yardley wrote in 2004, “it remains, decades later, the best of its kind.”

Sportswriter Jimmy Cannon called it “the greatest baseball book ever written,” but not everyone was as welcoming. Former player and broadcaster Joe Garagiola called Mr. Brosnan “a kooky beatnik” for exposing the game’s unsavory secrets. Frank Lane, general manager of the Cleveland Indians, called him “an intellectual meathead.”

In 1962, Mr. Brosnan published a second book, “Pennant Race,” which recounted the Reds’ surprising run to the National League title in 1961. Some critics thought it was even better than “The Long Season.”

One of the more poignant scenes in “Pennant Race” described the trade of the team’s longtime catcher, Ed Bailey:

“You’ve been with this club too long anyway,” Mr. Brosnan said, trying to console him.

“ ‘Yeah, ever since ’53,’ Bailey said. He paused and shook his head. He started to say something, then stopped, and remained silent for several minutes. . . . Finally, he said in a low voice, ‘It’s a funny feeling, you know?’

“Baseball is not the career for a man who needs security.”

James Patrick Brosnan was born Oct. 24, 1929, in Cincinnati. His father was a lathe operator for a milling company, and his mother encouraged the artistic interests of her children.

“I had no thoughts as a kid of being a major league ballplayer,” Mr. Brosnan told Rich Westcott for his 2000 book “Splendor on the Diamond.” “It never occurred to me. As a kid, I spent more time reading books than playing ball.”

But he grew tall, with a strong arm, and played on the same American Legion team in Cincinnati as future major leaguer Don Zimmer, who died June 4.

Mr. Brosnan began his professional career in the minor league system of the Chicago Cubs when he was 17.

He served two years in the Army in the early 1950s, pitching on the post team at Fort Meade, Md., and was preparing to study accounting when the Cubs brought him to the major leagues in 1954.

He had sporadic success with the Cubs and Cardinals before coming into his own as a relief pitcher in Cincinnati. Relying on a good fastball and devastating slider, he recorded a career-best earned run average of 2.36 in 1960. A year later, he won 10 games and saved 16, figuring in more than a quarter of his team’s 93 victories. The Reds went to the World Series, losing in five games to the New York Yankees, who were led by Roger Maris (61 home runs) and Mickey Mantle.

Mr. Brosnan finished his career with the Chicago White Sox in 1963. The next season, when club officials inserted a clause in his contract forbidding him from writing about baseball, he refused to sign it.

He retired to his home in Morton Grove, Ill., and wrote several children’s books about sports. He contributed hundreds of articles to Boys’ Life, Playboy and other magazines and also worked for many years as a television and radio sportscaster in Chicago.

In 1952, Mr. Brosnan married Anne Stewart Pitcher — “Pitcher marries Pitcher,” he often joked — who was a vivid presence in his books. She died last year.

Survivors include three children, Jamie Kruidenier of Champaign, Ill., Tim Brosnan of Morton Grove and Kimberlee Brosnan-Myers of Philadelphia; a brother; and four grandchildren.

Mr. Brosnan said it was no accident that he found his greatest success on the baseball diamond at the same time his writing career began to flourish with “The Long Season.”

“I’d always dwelled on my bad days, my embarrassments, and as a result, I was just competent,” he said in 1980. “The book finished that. It gave me the self-confidence I’d always lacked.”