With the centennial of the famed 1913 Armory Show in New York City approaching, now is the ideal time to examine fully, and for the first time, the life and work of Walter Pach, one of the prime movers behind this seminal event in the American art world. Pach was among the most influential figures in the history of twentieth-century art and culture, yet surprisingly little has been written about him—and much that has been written offers incorrect information. Pach was one of the earliest and most outspoken promoters of modern art and was Henri Matisse’s first agent in the United States. Through his multiple roles as critic, agent, liaison, and lecturer, Pach promoted modern European, American, and Mexican art and helped win its acceptance throughout the North American continent. Laurette McCarthy’s detailed account reintroduces us to this key figure in the world of modern art.