During his lifetime, Jean-Paul Sartre enjoyed unprecedented popularity for a philosopher, due partly to his role as a spokesman for existentialism—at the opportune moment when this set of ideas filled the spiritual gap left amidst the ruins of World War II. Existentialism was a philosophy of action and showed the ultimate freedom of the individual. In Sartre's hands it became a revolt against European bourgeois values.

In Sartre in 90 Minutes, Paul Strathern offers a concise, expert account of Sartre's life and ideas and explains their influence on man's struggle to understand his existence in the world. The book also includes selections from Sartre's work, a brief list of suggested readings for those who wish to delve deeper, and chronologies that place Sartre within his own age and in the broader scheme of philosophy.