A frequent theme in his work is the Second World War. His father had worked for the Germans during the war and went to prison for three years afterwards. As the war spanned most of Mulisch's formative phase, it had a defining influence on his life and work. In 1963, he wrote a non-fiction work about the Eichmann case: "Criminal Case 40/61". Major works set against the backdrop of the Second World War are "De Aanslag" (The Assault), "Het stenen bruidsbed", and "Siegfried".