Interest in marine mammals has increased greatly in recent years as our knowledge of them has grown. In particular the large cetacean brain and the supposed superior intelligence of marine mammals over other animals. In conjunction with their obvious diving and swimming abilities, this has made them fascinating creatures to study. Public involvement and the effort to conserve them from hunting by man and newly discovered ways of catching and maintaining them in captivity have all helped to increase their popularity and importance. In some cases this has resulted in the establishment of codes of practice for their capture, harvesting and transportation and has improved their lot from being mere objects of curiosity and participants in circus acts. However, the natural habitat of these animals has not facilitated a systematic investigation of them, and the marine mammalogist must necessarily specialize in one or a few types. It would be virtually impossible, therefore for a single author to compile a complete description of the whole range of the animals, from walruses and whales to dugongs and manatees. In the light of this consideration the "Handbook of Marine Mammals" was commissioned as a series of separate accounts of a single marine mammal. Each chapter is the outcome of many personal experiences of an international expert on the particular animal, and so includes subtle observations which might be unknown or overlooked by an ordinary reviewer. With the aid of distribution maps, identification pointers and photographs and drawings, as much as is known of each animal about its biology and life history is reviewed, and its identifying characteristics and distrubution described. Similarities and differences are stressed and some mention is made of economical and commercial aspects. A full bibliography is included for each chapter. It must be emphasized that these books are primarily a guide to the biology of marine mammals in their natural environment and are meant for use in the field as a practical aid to identification and to provide useful basic information, they are not concerned with management, husbandry or treatment of disease. The series presents authoritative coverage of all marine mammal species.