Lewis's first wife, Ernestina Corvaja, was a Swiss-Sicilian. Sicilian life, including the role of the Mafia, was a major theme, which he explored in "The Honoured Society" (1964) and "In Sicily" (2000). While never losing sight of the horrors inflicted by the Mafia, his accounts were not sensationalist. They were based on a detailed understanding of Sicilian society, and a deep sympathy with the sufferings of the Sicilian people. The Latin connection encouraged him to travel, resulting in his first book, "Spanish Adventure" (1935). The marriage had however failed by the start of the Second World War in 1939. He was briefly married a second time, after the war.