Pioneer of the Mexican steroid industry Russell E. Marker, one of the first American steroid chemists, discoverer of a plentiful source for our highlyprized steroid drugs and pioneer of the steroid industry in Mexico, disappeared completely from public view in 1949 at the height of his professional life. Since then numberless, diligent reporters have sought him out, hoping to regale their readers with news of the man whose achievements have altered the lives of a large portion of the world's population in making available the birth control "pill" (2). Most of them failed, and it had even been reported that he was dead. Recently however, a series of favorable circumstances made it possible for us to find him, to interview him and to organize an emotion-laden ceremony in which the Mexican Chemical Society honored him for his scientific achievements (3). This was the first public recognition of Russell E. Marker by the scientific community. It is the purpose of this biography to show that in addition to his well-known studies on steroids, he also made other important contributions to chemistry by his work on the fragmentation of organic mercury compounds, on the concept of octane number, on rearrangements in hydrocarbons and on the relation between optical rotation (including its dispersion) and configuration. It will show that he is indeed a forgotten great of chemistry whose scientific achievements should be better known (4).Education: Undergraduate Studies and Graduate Work at the University of Maryland At the end of his sophomore year at the University of Maryland, he was told by a friend that the basic organic course, which was given in the junior year, was the hardest subject of the program. Marker purchased a copy of the textbook used in the course (Norris) and during the summer