The letters published here for the first time document the unusual and not always easy friendship between Switzerland's two most famous 20th century writers: Max Frisch and Friedrich Dürrenmatt. The literary world linked Switzerland's two most famous 20th century writers inseparably together like a pair of comedians, something by which both authors were sometimes amused but more often irritated. Their common ground was their experience of Switzerland, isolated and spared from conflict between 1939 and 1945, and the guilt which the country incurred during World War II; their preoccupation with and different approaches to Kierkegaard and Brecht; their dissimilar but equally definite criticism of the army and anticommunism; their work at the Zurich Schauspielhaus theatre with the dramaturgist Kurt Hirschfeld whom they both admired. An epilogue by Peter Rüedi, for many years a critic of both authors, points out some connections between the letters, the authors' lives and work, and contemporary history.