Angle of Repose is a 1971 novel by American novelist Wallace Stegner about a wheelchair-using historian, Lyman Ward, who has lost connection with his son and living family and decides to write about his frontier-era grandparents. It won the Pulitzer Prize for Fiction in 1972. The novel is directly based on the letters of Mary Hallock Foote, later published as A Victorian Gentlewoman in the Far West.

Stegner's use of substantial passages from Foote's actual letters as the correspondence of his fictional character Susan Burling Ward was and remains controversial among some scholars. While Stegner's defenders have claimed that he had received permission to use Foote's writings, as the book's acknowledgments page implies, others point out that he secured that permission only after falsely claiming that his novel would not use any direct quotations.

In 1998, the Modern Library ranked Angle of Repose #82 on its list of the 100 best English-language novels of the 20th century.

The title, seemingly taken from Foote's writings, is an engineering term for the angle at which soil finally settles after, for example, being dumped from a mine as tailings. It seems to describe the loose wandering of the Ward family as they try to carve out a civilized existence in the West and, Susan hopes, to return to the East as successes. The story details Oliver's struggles on various mining, hydrology, and construction engineering jobs, and Susan's adaptation to a hard life.

Another view has to do with a typical construction of canals and the drowning of Ward's daughter in a canal. Canal banks are sometimes simply piled mounds of dirt. Slanted walls of dirt are left at the angle of repose after the canal is built. Small disturbances to the dirt can cause it to slide down. Ward's daughter fell into a canal and couldn't climb out because of this.

Lyman Ward narrates a century after the fact. Lyman interprets the story at times and leaves gaps that he points out at other times. Some of the disappointments of his life, including his divorce, color his interpretation of his grandparents' story. Toward the end of the novel, he gives up on his original ambition of writing a complete biography of his grandmother.

Stegner's use of Mary Hallock Foote's historical letters gives the novel's locations—Grass Valley, Leadville, New Almaden, Idaho, and Mexico—an authentic feel; the letters also add vividness to the Wards' struggles with the environment, shady businessmen, and politicians. Lyman's position in the contemporary culture of the late sixties provides another historical dimension to the story. Foils for this plot line include Lyman's adult son, a UC Berkeley-trained sociologist who sees little value in history, and a neighbor's daughter who helps transcribe Lyman's tape-recorded notes while she is home on summer break from UC Berkeley, where she has been active in the "hippie" counterculture movement.

58-year-old retired history professor Lyman Ward is the narrator of the book. He is a divorced amputee with a debilitating disease that is slowly "petrifying" him. The text of Angle of Repose is transcribed tapes of Ward dictating what is to become the biography of his grandmother, Susan Burling Ward. The dictation begins on April 12, 1970, and continues through the summer. Fiercely independent, Ward lives alone at the Zodiac Cottage, the house where his grandmother spent the last decades of her life and in which he spent time as a child. "Because of his disease and because his wife has abandoned him, [Ward] has reached a major crisis point in his life...His crisis leads him to the need to find a direction for his shattered life. That direction is provided by finding out about and trying to understand his grandparents..."