As I Lay Dying
While I greatly prefer my own assigned high school read The Sound and the Fury, the backstory on this slim novel is truly astounding. Faulkner claimed that he wrote it in 6 weeks, working from midnight to 4:00 a.m., and that he didn't change a word. The story, again set in Faulkner's Yoknapatawpha County, Mississippi, is narrated by 15 different characters over 59 chapters. Consistently cited as one of the best novels of the 20th century, both for its own sake and for the great influence it had over subsequent fiction.
Publisher’s description:
As I Lay Dying is Faulkner’s harrowing account of the Bundren family’s odyssey across the Mississippi countryside to bury Addie, their wife and mother. Narrated in turn  by each of the family members—including Addie herself—as well as others the novel ranges in mood, from dark comedy to the deepest pathos. Considered one of the most influential novels in American fiction in structure, style, and drama, As I Lay Dying is a true 20th-century classic.