This is an appreciation of the many contributions to the field of chemistry by Professor Trevor M. Letcher in the year of his 80th birthday. Professor Letcher has published on chemical education, the thermodynamics of solutions, practical industrial applications, and edited a number of special books on various subjects such as the environment and thermodynamic relationships, among many other subjects. Included herein is a brief biography, a bit about his family, a brief discussion of several publications, a list of his edited books, and an introduction to the papers submitted in his honour. (c) 2018 Elsevier Ltd.