American modernist John Marin (1870-1953) worked prolifically in watercolor, etching, and oil during a career that spanned more than 50 years. It was the medium of watercolor, however, that encouraged him in his development of a bold, original style that is both contemporary and authentically American. Marin's improvisational approach to color, paint handling, perspective, and movement situated him as a leading figure in modern art and helped influence the Abstract Expressionist movement. John Marin's Watercolorsis the first book to present the Art Institute of Chicago's impressive collection of his works in its entirety, ranging from early images rooted in traditional practice to more experimental compositions. It explores the artist's working method, his modernist vision as it developed through etching and into watercolor, and his intuitive investigation of the inherent properties of his watercolor to craft a new, avant-garde methodology. The works are organized chronologically and grouped according to the sites where they were painted, including New York City, France and the Tyrol, the Maine coastline, and the New Mexico desert. Marin had a strong regard for the presentation of his watercolors, and a section illuminates how he chose frames and mounts for each work. The Art Institute's significant collection of Marin's original frames and mounts were bequeathed to the museum, along with some 50 watercolors, by legendary photographer, dealer, and collector Alfred Stieglitz. Marin's and Stieglitz's attitudes toward presentation are discussed, and the frames are documented with photographic and written descriptions.