Pierre; or, The Ambiguities is the seventh book by American writer Herman Melville, first published in New York in 1852. The novel, which uses many conventions of Gothic fiction, develops the psychological, sexual, and family tensions between Pierre Glendinning; his widowed mother; Glendinning Stanley, his cousin; Lucy Tartan, his fiancée; and Isabel Banford, who is revealed to be his half-sister. According to scholar Henry A. Murray, in writing Pierre Melville "purposed to write his spiritual autobiography in the form of a novel" rather than to experiment and incidentally work some personal experience into the novel.
Published after the lukewarm reaction to Moby-Dick, Pierre was a critical and financial disaster. Reviewers universally condemned its morals and its style. More recent critics have shown greater sympathy toward the book, seeing it as a "psychological novel – a study of the moods, thought processes, and perceptions of his hero".