In The Catcher in the Rye, Holden Caulfield's younger brother Allie dies from leukemia. Also mentioned in the book is the suicide of a former schoolmate of Holden's from Elkton Hills, James Castle, who jumped out the window at school while wearing a sweater that he borrowed from Holden.
Other than these two, there are no other deaths mentioned in the novel. The death of innocence is a main theme that preoccupies Holden throughout the novel. He resists growing up, he resists taking responsibility for his life and would rather return to childhood. As a 16 year old boy, this causes him to continue to fail out of one school after another for not applying himself to his schoolwork.
Holden thinks about his own death in the novel, while sitting on a bench in Central Park, shivering with cold and wondering where the ducks have gone for the winter. He considers sitting there and allowing the weather to give him pneumonia, but then decides that it would hurt his little sister Phoebe if he died, so he leaves the frozen park.
He longs to be a catcher in the rye, his dream job, where he would, literally, catch children as they reached the edge of the field of rye, symbolically representing childhood, so that they would never have to grow up.
Allie - Holden's younger brother who died of leukemia. Also might be the cause of Holden's Isolation.
James Castle- A quiet, and weak looking classmate who refused for insulting one of his classmates. Ended up committing suicide by jumping out of a window. He is one of the main reasons Holden does not want to commit suicide.