Description: This is the second volume of the entirely rewritten, revised and updated version of the original FAO Catalogue of Cephalopods of the World (1984). The present Volume is a multiauthored compilation that reviews 28 families, i.e. (in alphabetical order), Ancistrocheiridae, Architeuthidae, Australiteuthidae, Bathyteuthidae, Batoteuthidae, Brachioteuthidae, Chiroteuthidae, Chtenopterygidae, Cranchiidae, Cycloteuthidae, Enoploteuthidae, Gonatidae, Histioteuthidae, Joubiniteuthidae, Lepidoteut hidae, Loliginidae, Lycoteuthidae, Magnapinnidae, Mastigoteuthidae, Neoteuthidae, Octopoteuthidae, Ommastrephidae, Onychoteuthidae, Pholidoteuthidae, Promachoteuthidae, Psychroteuthidae, Pyroteuthidae and Thysanoteuthidae, with 83 genera and the 295 species known and named to the date of the completion of the volume. It provides accounts for all families and genera, as well as illustrated keys. Information under species accounts includes: valid modern systematic name and original citatio n of the species (or subspecies); synonyms; English, French and Spanish FAO names for the species; illustrations of dorsal and ventral aspects of the whole animal (as necessary) and other distinguishing illustrations; field characteristics; diagnostic features; geographic and vertical distribution, including GISmap; size; habitat; biology; interest to fishery; local names when available; a remarks section (as necessary) and literature. The Volume is fully indexed and also includes sectio ns on terminology and measurements, an extensive glossary, an introduction with an updated review of the existing biological knowledge on squids (including fisheries information andmain catch data for recent years) and a dedicated bibliography. Due to the conspicuous amount of literature addressingmany squid species, an appendix is included in the online version, where those references considered most pertinent to the species are listed, by family and species, in alphabetical order by au thor; key words, also, are reported.