This article, and this issue of the AIChE Journal, is a tribute to Professor James (Jay) E. Bailey who, as an intellectual leader of biochemical engineering, has had a profound impact on chemical engineering. Over his 30-year career, Bailey pioneered many new approaches that have become cornerstones of modern metabolic engineering, enzyme engineering, and cell culture engineering. We highlight some of these seminal contributions as well as his legacy as a research mentor. (c) 2018 American Institute of Chemical Engineers