Although he has been dead for about three years, Allie is a mystic presence in the novel. Holden thinks of him often and speaks to him when things are darkest in his life. Allie is associated with the theme of death, but his role is not that simple. He also represents hope and the gifted innocence of childhood, which is tenuous and sometimes short-lived. Holden clearly loves his brother. Only two years apart in age, they were close friends.
Allie died of leukemia at the Caulfields' summer home in Maine on July 18, 1946. He was 11 years old; Holden was 13. Holden, distraught over the loss of his brother, broke his hand punching the windows out of the garage of their summer home. Holden missed Allie's funeral because he was in the hospital, apparently for psychiatric evaluation as well as for attention to his hand. Depending on the date of Holden's birthday and his precision with numbers, that was about four years before Holden tells the story (at age 17) from the sanitarium in California and perhaps three and a half years before Holden (age 16) leaves Pencey. Allie was the most intelligent as well as the "nicest" member of the family. His connection to Holden was intense. The older brother could sense when Allie was in the vicinity, although he credits Allie's red hair for that. Holden would get a hunch that Allie was there; when he turned around, there Allie was.
Allie's left-handed baseball glove is a symbol of his unique personality as well as Holden's love for his brother. The unique part of the glove is that Allie wrote poems all over it, in green ink. He did that so he would have something to read when he was in the baseball field and the game was boring. Holden keeps the glove with him and has it at Pencey. It is, of course, misguided to think that the boorish Stradlater, Holden's roommate, could understand or appreciate the essay that Holden writes about the glove. Stradlater wants something descriptive to hand in to his English teacher and is too lazy and dull to do the work himself. He asks Holden to write it. Telling someone like Stradlater about the glove is a sacrilege. Allie is more than a brother to Holden. In Holden's chaotic cosmos, he is an angelic presence, a connection to death but also to hope.