The success of the previous volumes in this series attests to the buoyancy of the current expansion of the aquaculture industry, and the importance which it is beginning to achieve in the rural economies of many developed countries as well as those less favoured. In the last volume, emphasis was given to certain specialist areas which had become more important as the industry had acquired a more sophisti­ cated scientific base. This emphasis is continued, but in each of the chapters of the present volume there are, we believe, many data of general significance to the farmer and the project manager as well as to the pro­ fessional aquaculture scientist. David Alderman, of the English Ministry of Agriculture, Fisheries and Food Laboratories, at Weymouth, Dorset, provides a very detailed and deeply researched review of therapy of fish diseases. This subject is import­ ant in environmental and human health terms as well as in relation to the fish themselves, and is an area where all farmers, and their professional veterinary advisers, require considerable knowledge if they are to ensure the reputation of the industry and its produce.