The Boys of Summer is a nonfiction book about baseball by American writer Roger Kahn. The book was published in 1972. The first and most prominent theme of the book is the game of baseball from the perspective of an avid fan. In particular, the book is from the perspective of a young New Yorker who watched the local teams—as well as those they competed against—through the early to mid-20th century. The evolution of modern baseball is detailed in Kahn's book, and shows the minor and major events that contributed to the game's development as a national pastime.

A significant part of the book's prose stems from Kahn's own childhood and his interpretation of his memories growing up. In this regard, the other prominent theme of the book is the autobiographical narration of a childhood in New York City. The city and particularly the borough of Brooklyn, where Kahn grew up, is the other major theme of the book. Baseball and New York City are closely tied together culturally. One of the city's teams, the New York Yankees, which played in the Bronx, has won more championships than any other team in baseball. Going to watch the local teams at the stadium on weekends, or listening to the baseball game broadcasts on the radio, became family traditions for many households in the tri-state area.

Kahn writes about his childhood memories as if baseball was the marker for his own growth as a person. Baseball, like religion, came to signify important events in one's life in the same way a baptism, wedding, confirmation or funeral marked the major transitions in a Catholic's life.

In fact, one of the other major themes in the book is the depiction of baseball as a kind of new American-made religion. Whilst Kahn does not blatantly state this, reviewers and critics of the book noted Kahn's overwhelming sentimentality and veneration towards the game that he loves.