Julius Ralph Davidson is widely known as the architect of Thomas Mann’s house. Born 1889 in Berlin, Davidson left Germany in 1923 and emigrated to the USA. In Los Angeles, he designed some 150 projects, among them three houses for the experimental Case Study House Program. This long overdue publication is a comprehensive documentation of Davidson’s life and work, highlighting J.R.‘s contribution to modernism in California in the 1930s and 1940s.