An account is given of Ronald Gillespie's career and his scientific contributions to research and to chemical education from the perspective of the author, an accomplice who for more than 40 years has profited enormously from countless long hours of scientific discussion and beneficial comradeship. His career is charted from his early fascination with chemistry, through his university experience at University College, London, where he benefited greatly from the influence of Sir Christopher Ingold, to his long association with McMaster University, and his continuing unremitting activity in retirement. A personal account is given of some of his major contributions, including his pioneering work on superacids, his seminal work in furthering our understanding of the factors that influence molecular structure and bonding through his valence shell electron repulsion (VSEPR) and ligand close-packing (LCP), models, and his contributions to chemical education. (C) 2000 Elsevier Science S.A. AU rights reserved.