Marcel Proust’s A la recherche du temps perdu (1913–27) is a modern classic, arguably the most influential French novel of the twentieth century. This chapter examines its landmark status, its composition, structure and thematic preoccupations. It investigates why Proust’s novel stands apart from others produced contemporaneously and why its appeal endures to this day. Proust’s novel is shown to be a work characterized by plurality and multiplicity, an echo chamber of earlier works of art, and a vital staging post in the history of the novel. The reception of Proust's novel is considered, together with its place in the development of European modernism. Its long gestation and piecemeal publication are discussed and related to contemporary publications and the ways in which Proust adapted his novel and its architecture to the events—geopolitical and personal—that occurred during this time. The chapter examines the demands made of Proust’s readers by his narrative techniques and the strategies we develop to cope with the scale and ambition of his novel. It closes with a reflection on the ways in which twentieth- and twenty-first century French novelists have responded to Proust’s achievements.