Lampreys are aquatic, jawless vertebrates widely found in the Northern and Southern hemispheres, but virtually absent in the intervening tropical zone. Lampreys undergo a radical metamorphosis from the larval to the adult form. The adults vary considerably: some are parasitic and anadromous, others parasitic but restricted to fresh water, while still others are nonparasitic (non–feeding) and restricted to fresh water. A new issue of the FAO Species Catalogue for Fishery Purposes presents an annotated and illustrated catalogue of lamprey species known to date. It explains and illustrates the taxonomic characters used to describe ammocoetes and adults; presents a key to adults and a partial key to larvae and provides an account for each of the 39 species with information on the taxonomy including synonyms, common names, diagnostic features of ammocoetes and adults (with drawings of the adult body and oral disc), habitat and biology, geographic distribution (with map), interest to fisheries and references.