Frans Verdoorn was born at Amsterdam in 1906. When young his main biological interest was in the taxonomy of Hepaticae; later it was in the history of biology. His active career as a bryologist began about 1926 when he was a schoolboy and ended about 1939. In 1940 he moved to the United States and returned to Holland in 1957 to become Director of the Biohistorical Institute at the University of Utrecht. He had a very important influence on the revival of bryology immediately before and after the Second World War. This was mainly through his work as editor of the Manual of Bryology (1932) and other publications. A bibliography of Verdoorn's bryological works is included.