One California Architect, Irving J. Gill, is an update and republication of Esther McCoy's groundbreaking chapter on Gill in her seminal 1960 work Five California Architects. It gives a comprehensive look at Gill's life from his youth in Syracuse, New York, to his apprenticeship in Chicago with Adler & Sullivan, his move to San Diego in 1893, and the evolution of his work into what we now call Modern Architecture. McCoy's book was the first to document the progressive architectural movement that emerged in California at the turn of the last century. Her writing on Irving J. Gill was especially important as it opened the world's eyes to the first Modern Architecture, as created by Gill in San Diego and Los Angeles. Her work on Gill is being republished in this enhanced edition by the Irving J. Gill Foundation in this, the 150th year since Gill's birth. This new edition also celebrates the 60th anniversary of Five California Architects and includes enhanced images and updated information not available to McCoy. All profits go to the Irving J. Gill Foundation.