Abstract
During the past thirty years significant contributions to our understanding of the structural origins of the catalytic power of enzymes have come from solution and crystallographic studies of enzyme-substrate and enzymeintermediate complexes trapped at subzero temperatures, a field that was pioneered in large part by Anthony L. Fink and Pierre Douzou. Here I review, from a personal perspective, the history of crystallographic cryoenzymology, with an emphasis on the contributions of Tony Fink. The story has a moral: if you choose your collaborators based not only on their scientific prowess but also on their human qualities, the resulting friendships will enrich your life.