Jack Fowler [formally Professor John Francis Fowler PhD, DSc, MD (Hon), FInstP, FRCR, FBIR, FAAPM, FASTRO, FACRO] was a remarkable scientist, known to many in the field of clinical radiation biology as at the forefront of applying linear-quadratic dose-fractionation-time modelling to help improve a wide range of cancer treatments using radiotherapy. His death on 1st December 2016 after a long career of 60 years was marked by Obituaries in six scientific journals in his field e.g. Jack is remembered for his quantification of biologically effective dose in a wide variety of radiotherapy practices and modified protocols (supported by experimental-system studies), his extensive publications, his didactic lecturing and teaching abilities, and his warm personality.