William Taylor Marshall (1886–1957) was a leading researcher in cactus taxonomy over a 25-year period, notably based on fieldwork in Mexico and the deserts of southwest USA (1933–1957). His publication output is assessed and documented fully for the first time. Notable are the books Cactaceae (1941), co-authored and illustrated by T.M. Bock, and Succulent Plants (1945), co-authored with Rupert Leach and accompanied by a unique set of 3D slides. His journal articles were prolific, published in many C&S titles around the world. A major vehicle for his publications was Saguaroland Bulletin which he established in 1947. He was Cactus & Succulent Society of America President (1938–1941), then President Emeritus until his death, during which time he initiated the biennial CSSA conventions. As it stands today, the Desert Botanical Garden in Phoenix, Arizona, where he was Director (1947–1957), with its living collections, library and herbarium, is a major Marshall legacy.