In his first fourteen seasons, as a pitcher for the Giants, Mathewson never won fewer than twenty games in a season, and he almost single-handedly won the 1905 World Series. In 1918, though age thirty-eight and exempt from military service, he enlisted for World War I, where he exposed himself to nearly lethal amounts of mustard gas as he taught soldiers how to put on gas masks. When he returned home, he was diagnosed with lung problems and tuberculosis, which led to his untimely death at the age of forty-five.

After Mathewson's death, his eulogies were many, but it was impossible to catch the essence of his life in a single newspaper column. Jane Mathewson, his widow, was determined to provide the reading public with a more intimate portrait of her husband and approached prominent sportswriter Bozeman Bulger, who had known Mathewson for twenty years. Bulger wrote a series of articles titled "The Life Story of Christy Mathewson." His portraits about the player were amplified by original accounts from Jane, and several unpublished chapters from Mathewson himself, which had been discovered among his papers. These combined accounts allow readers to hear from Mathewson and those who knew him best.

A superstar long before that term was coined, Mathewson became an icon of sportsmanship. He was posthumously elected to the Baseball Hall of Fame at its first induction ceremony in 1936. In Baseball's First Superstar Alan D. Gaff brings Mathewson to life through Mathewson's own writings and those of others, largely lost to history until now.