We were immensely saddened to learn that Professor John Lewis had passed away on the night of 13 December 2022 at the age of 84. John was Emeritus Professor of Zoology at Royal Holloway, University of London, where he began as a lecturer in 1963 and was awarded a University of London Chair in Zoology in 1992. He was one of the founding members of the British Society for Parasitology (BSP), for which he organized several meetings and in which he participated actively long after retiring from Royal Holloway in 2003. John was elected an Honorary Member of the BSP in 2003 and was also a Fellow of the Linnean Society and of the Royal Society of Medicine. He served as Dean of Science and Head of the Centre for Environmental and Evolutionary Biology in the School of Biological Sciences at Royal Holloway. John was Editor of the Journal of Helminthology (JHL) for 22 years (from 1994) and then supported the journal further as Emeritus Editor, until his final year.

John was one of the early pioneers of the ecology of helminths in British wild rodents. He began his scientific career in the early 1960s investigating the helminths of wood mice, voles and shrews in several disparate sites in West Wales, while a PhD student under the supervision of Professor Gwendoline Rees FRS, at University College of Wales in Aberystwyth (Lewis, Reference Lewis1964, Reference Lewis1968a, Reference Lewisb). This topic fascinated John throughout his scientific career and was one in which he retained an interest until the very end of his life. Even in his last year, while fighting Hodgkin's lymphoma, he provided the inspiration and drive for the completion of his final scientific paper on this topic (Lewis et al., Reference Lewis, Morley and Behnke2023), a truly remarkable example of his dedication to science and parasitology.

John's early years at school, then university (he was awarded his PhD in 1964) and his subsequent scientific career are all meticulously recorded in Rollinson (Reference Rollinson2018), which also details his work as editor of the JHL and his contribution to the administrative activities at Royal Holloway, University of London. John's research centred around three themes in each of which he supervised postgraduate students and fostered many collaborations both nationally and internationally. Besides the helminthology of rodent hosts, he also developed a keen interest in aquatic parasitology and toxicology, and a comprehensive list of his publications is given in Rollinson (Reference Rollinson2018) and in the supporting Online Supplement (supplementary table S1).

John was a passionate Welshman, and an enthusiastic rugby fan, a lovely man who was kind and courteous to all. He was very much liked by all who knew him and who enjoyed a pint or two with him at scientific meetings, and during his visits as external examiner at other universities. He was a much-respected teacher of undergraduate courses in parasitology and a popular external examiner for undergraduate biology and zoology courses. He was also a thorough, but extremely diplomatic external examiner of postgraduate students. His calm, relaxed nature and constructive approach to viva examinations quickly put candidates at ease generating a memorable experience for those involved. John leaves an outstanding legacy in the disciplines of mammalian and aquatic parasitology, and toxicology. The foundations he laid over his memorable career will continue through the many young scientists with whom he was associated.

John leaves his wife Ann, two sons, two daughters and six grandchildren, and will be sadly missed by his family and by all who knew him as a friend, colleague or collaborator.