In Search of Lost Time also translated as Remembrance of Things Past—is a novel in seven volumes by Marcel Proust (1871–1922). His most prominent work, it is known both for its length and its theme of involuntary memory, the most famous example being the "episode of the madeleine."

The novel began to take shape in 1909. Proust continued to work on it until his final illness in the autumn of 1922 forced him to break off. Proust established the structure early on, but even after volumes were initially finished he kept adding new material and edited one volume after another for publication.