Leo Stein had little direct influence on the generation of writers and painters who gathered in Paris during the twenties. Yet between 1904 and 1910 Stein was the primary collector of and propagandist for the modern art hung at 27, rue de Fleurus, the residence which he shared with his younger sister, Gertrude Stein. During these years he dominated their Saturday evening gatherings with his analytical lectures on such figures as Pierre Auguste Renoir, Paul Cezanne, Henri Matisse, and Pablo Picasso. Though he soon lost faith in the direction of most modern art, including his sister's writing, he was clearly instrumental in establishing both a subject matter and an important setting for the artistic and literary renaissance of the twenties.

Born to Daniel and Amelia Keyser Stein in Pittsburgh, Pennsylvania, and raised primarily in Oakland, California, Stein spent much of his childhood traveling with his family in Europe. He studied history...