Art critics commonly describe the work of Belgian artist Jef Geys (1934-2018) as “unruly, and impossible to categorize in conventional art-historical categories.” Despite Geys’ subversive and critical attitude towards the art world, this ambitious publication shows that his work is not only deeply engaged and socially critical but also funny and sensory. Since the early 1960s Geys had compiled an archive of everything he considered part of his artistic practice in to form of his ‘List of Works’ serving as his oeuvre's index. With a total of 844 entries, Catalogue Raisonnable, is the first total survey of Jef Geys’ work. Through access to the artist’s archive, close collaboration with Geys’ next of kin, and thorough art-historical research, this publication offers a rare opportunity for understanding and appreciating the fascinating practice of one of Belgium's greatest artistic figures.