In form, The Tin Drum is the autobiography of Oskar Matzerath, thirty years old, detained in a mental hospital, convicted of a murder he did not commit. It is taken down with the aid of his tin drum - the chosen symbol of his way of life - which helps him to remember his checkered past.

Oskar's father is a German, who runs a grocer's shop in Danzig and later becomes an undistinguished S.A. man. But his mother's lover and cousin, the Pole Jan Bronski, is dearer to Oskar than Matzerath, and the boy believes Jan to be his natural father. Pole or German, Oskar is born with an almost adult mind. On the day he is born he hears his parents discussing their plans for his future and decides to thwart them. At the age of three he stages a fall down the cellar steps and remains for many years three feet tall and in appearance and speech a child. On the same day Oskar's mother gives him his first tin drum and from then on it is the means of his expression.

Drum succeeds drum as the fearful years of the Hitler epoch ebb bloodily away. With his drum Oskar breaks up Nazi meetings, with his high-pitched scream he shatters everything from spectacles to plate-glass windows. For Oskar is an anarchist, and within the ivory tower of his assumed childishness, he expresses his individualism in themes that are grotesque, ribald and sadistic.

At the end of the war, Oskar flees to West Germany where he becomes part of the economic miracle, working variously as a blak marketeer, an artist's model, and a night-club performer. He has also decided to grow several linches, and in doing so develops a hunchback. He becomes successful, affluent, even famous, but behind his new stature lies a feeling of guilt for the deaths of his parents and other past sins. And so his assumption of the guilt for the murder he did not commit is an act of atonement, and a realization of the mad state of the modern world in which, Grass implies, we are all moral hunchbacks.