Mann became famous with the publication of his first novel, Buddenbrooks (1901, tr. 1924), which depicts the rise and disintegration of a merchant family. Shorter works of fiction followed, among them Tonio Kröger (1903, tr. 1913–15); the verse drama Fiorenza (1905); and the classic Der Tod in Venedig (1912, tr. Death in Venice, 1925), a novella in which the hero, a great writer, falls prey to an uncontrolled passion, weakens, and eventually dies. These works show Mann's preoccupation with the interaction of cultural and psychological problems. The proximity of creative art to neurosis and the affinity of genius and disease are his largest themes, along with a strong interest in the nature of repressed, often homoerotic sexual desires.
Artistic values in a bourgeois society is a main theme in his rather comic second novel, Königliche Hoheit (1909, tr. Royal Highness, 1916). Among Mann's other important shorter works of fiction are Unordnung und frühes Leid (1925, tr. Early Sorrow, 1929), a story; and the short novel Mario und der Zauberer (1930, tr. Mario and the Magician, 1930), an allegorical attack on fascism.
Translations of his shorter fiction are collected in Stories of Three Decades (1936). Mann's third novel, Der Zauberberg (1924, tr. The Magic Mountain, 1927, 1995), occupied him for 12 years. Here the protagonist is a young man from a middle-class background who, after spending seven years in the midst of discussions of disease and death in a tuberculosis sanatorium, finds fulfillment in leaving to re-enter the larger world.
Mann then began his tetralogy Joseph und seine Brüder (1933–43, tr. Joseph and His Brothers, 1934–44), on which he worked intermittently for 16 years. This erudite and detailed recreation of the biblical story of Joseph is a brilliant study of the psychological and the mythological. In Doctor Faustus (1947, tr. 1948), Mann used the Faust motif to delve into the conflict between spirituality and sensuality. His last works include the novels Der Erwählte (1951, tr. The Holy Sinner, 1951) and Bekenntnisse des Hochstaplers Felix Krull (1954, tr. Confessions of Felix Krull, Confidence Man, 1955), a picaresque comedy adapted from an earlier fragment.