From time to time, SULFUR REPORTS plans to invite distinguished chemists to summarize the research of their careers as it has related to sulfur chemistry. This contribution by Professor C. S. Marvel, the first such account, is an informal resume of his research with organic sulfur compounds that has occurred in a career spanning more than 60 years. Professor Marvel received his Ph.D. degree at the University of Illinois (Urbana) in 1920. He remained there on the faculty until he became Professor Emeritus in 1961 and relocated to the University of Arizona, where he has continued his research vigorously. His recognition as a towering figure in organic and polymer chemistry of the twentieth century is illustrated by award to him of the Priestley, Perkin, Nichols, and Gibbs medals, along with a host of named lectureships, honorary degrees, and other awards. He has been a member of the National Academy of Sciences (U.S.A.) since 1938 and has served as President of the American Chemical Society (1945) and on numerous editorial boards and advisory panels. An instructive (and entertaining) autobiography appeared in CHEMTECH, 10, 8–11 (1980). Although Professor Marvel's primary career interest has been in polymers, he has made many significant contributions to organic sulfur chemistry; these are described in 100 publications listed in the bibliography. His present account describes his adventures with polymeric sulfides, disulfides, thiol esters, mercaptals, and sulfones. His research has not been confined to polymeric compounds, however, and he summarizes contributions as well to the chemistry of many classes of sulfur compounds, including thiols, disulfides, thio acids, sulfinic and sulfonic acids and derivatives, and sulfur-containing heterocycles.