Thomas Arthur Steitz. 23 August 1940—9 October 2018

Thomas A. Steitz was among the foremost of the generation that was responsible for an explosion in our understanding of the structure and function of biological macromolecules. His research career was one of sustained excellence over six decades, and spanned the range from determining the structures of important metabolic enzymes to understanding the structural basis of how genetic information residing in our DNA is used to make the proteins they encode. This latter effort culminated in the structure of the ribosome, for which he shared the Nobel Prize in Chemistry in 2009.