Harvey Penefsky was a highly admired and beloved PHRI faculty member for more than 40 years, and a giant in the fields of Bioenergetics and Enzyme Kinetics. Harvey, who often dressed in a tie, white shirt and jacket, always displayed a calm, distinguished and unassuming demeanor that belied his scientific brilliance. He was a Chicago native who served in the Army. He obtained a BA from New York University (NYU) in 1956 and a PhD from NYU in 1960. His thesis work with Efraim Racker (PHRI) and Maynard Pullman (PHRI) on the isolation of the ATPase (F1) factor responsible for oxidative phosphorylation was a key advance for biological sciences (see attached). This work led to the biochemical and kinetic characterization of the ATP synthase and the introduction of enzyme reconstitution studies in the Racker lab. Harvey joined the PHRI staff in the early 1960s. In the 1980s, along with Richard Cross (SUNY Upstate) and Charlie Grubmeyer (PHRI), Harvey’s kinetic insights into the ATP synthase led to a series of landmark papers that transformed our current understanding of the mechanism of the ATP synthase. This elegant kinetic work (involving non-steady-state kinetics) explained how electrochemical energy is used during the formation of ATP by the ATP synthase. It determined that ATP is formed in catalytic sites on the F1 complex from bound ADP and Pi with virtually zero change in free energy and that the major requirement for energy in oxidative phosphorylation is for the release of product ATP from high affinity catalytic sites. This conformational coupling work was pivotal for Paul D Boyer, who received the 1997 Nobel Prize for elucidating the enzymatic mechanism of the ATP synthase. (Many people in the field believed that Harvey should have shared in that award.) Harvey was active well into his 80s until his health waned. Dr. Zia Penefsky, his wife of 61 years, died in 2015. In addition to PHRI. Harvey was a faculty member of SUNY Syracuse from 1988-1996, and a member of the NJMS’ Department of Microbiology and Molecular Genetics from 2002-2007. To most, Harvey was a science luminary whose biological insights and brilliance will live forever in textbooks. As a PHRI colleague, he was a kind hearted and wonderful friend.