John M. Lyle (1872--1945) was an anomaly among architects: a Beaux-Arts classicist who nevertheless found much inspiration in modernism, allowing his own traditionalist practice to be affected in form and detail by a brave new emphasis on minimalism and indigenous influence. His early works, including countless legendary banks and residences, as well as the iconic Union Station and Royal Alexandra Theatre in Toronto, are exemplary of Beaux-Arts classicism; his later bank designs in Halifax, Calgary and Toronto display a modernist shift and see him championing an idiosyncratic and authentic regional consciousness. A Progressive Traditionalist traces this aesthetic trajectory through the tumultuous first half of the twentieth century, documenting Lyle's training at Yale and in Paris, his early career in New York and his later success in Toronto, including his tireless efforts to raise the profile of the profession through teaching, writing, curating and lecturing, and his attempts to pave the way for a uniquely Canadian architecture.