This publication is the result of a course on identification of Hymenoptera given three times since 1985 at the Centre for Land and Biological Resources Research. The considerable interest in these courses indicated the need for a comprehensive identification guide to all extant families of Hymenoptera. The main emphasis is on family identification using the keys, which are complemented by family sketches. The sketches include a taxonomic diagnosis to supplement the keys, a summary of the biology, the size and distribution, and important literature references.