Mark A. S. McMenamin is a geologist and paleontologist in the department of Geology and Geography at Mount Holyoke College. His research career has focused on the geological and especially paleobiological events that took place during late Proterozoic time. He has a special interest in the Ediacaran biota, Cambrian small shelly fossils, archeocyaths, and trace fossils of the Proterozoic-Cambrian transition interval. He also has participated in research that led to the naming of the supercontinent Rodinia. Mark discovered a “deep Proterozoic” assemblage of Ediacaran fossils and trace fossils in the Cerro Rajón, Sonora, Mexico. Basing his conclusions on theoretical considerations, Mark correctly predicted that conularids would be found among the Ediacaran biota. Mark’s work on the Cambrian shelly fossil genus Mickwitzia helped to define this group as a stem-group (and possibly pre-bivalved) type of early brachiopod. His work on Vermiforma from North Carolina has shed new light on this enigmatic trace fossil. Mark recently revised the taxonomy of the Ediacaran Pteridinium carolinaensis and also named the a new Cambrian trilobite species Paradoxides from the Carolina Slate Belt. Mark is currently assisting in the effort to define the relationship of continental blocks such as Avalonia and the Carolina Terrane to larger continents as a means of refining the Rodinia reconstruction. Mark’s books include The Emergence of Animals (with Dianna McMenamin, Columbia University Press); Hypersea: Life on Land (with Dianna McMenamin, Columbia); and The Garden of Ediacara: Discovering the First Complex Life (Columbia). With Gregory Jenkins, Christopher McKay, and Linda Sohl, Mark co-edited The Extreme Proterozoic: Geology, Geochemistry, and Climate (American Geophysical Union). Mark also edited the English versions of Vladimir Vernadsky’s groundbreaking book The Biosphere (Copernicus/Springer Verlag) and Corneille-Jean Koene’s pioneering work The Chemical Constitution of the Atmosphere from Earth’s Origin to the Present, and its Implications for Protection of Industry and Ensuring Environmental Quality (Edwin Mellen Press).