I have the sad honour to announce the passing of Rudger Kieboom (1950-2022), Professor Emeritus at the Vrije Universiteit Brussel (VUB). His enthusiasm for Category Theory influenced several master students at the VUB. Philippe Cara, Tomas Everaert and I made our Ph.D.'s under his guidance. After an initial two years of studies in his home town Antwerp, Rudger obtained both his M.Sc. (1970) and Ph.D. (1976) at the VUB, where he would work for 45 years in total. His main mathematical interest was in classical homotopy theory (diverse types of (co)fibrations, homotopy lifting and extension properties), work which gradually became more categorical, with later results in a 2-dimensional and in an internal-categorical context. Rudger was a friendly, good-humoured man, who enjoyed a good discussion over a glass of beer. Apart from science, mathematics, horror movies and philosophy, he was passionate about jazz: he would never miss an edition of Antwerp's yearly jazz festival. Unfortunatly, at the end of his active career, Rudger was diagnosed with Alzheimer's disease. This caused him to be hospitalised suddenly, seven years ago. His disease soon made any type of contact impossible, so in this sense we have already had to miss him for several years. Tim Van der Linden [For admin and other information see: http://www.mta.ca/~cat-dist/ ]