The predecessor to this book was A Guide to the Laboratory Use of the Squid Loligo pealei published by the Marine Biological Laboratory Woods Hole Massachusetts in 1974. The revision of this long out of date guide with the approval of the Marine Biological Laboratory is an attempt to introduce students and researchers to the cephalopods and particularly the squid as an object of biological research. Therefore we have decided to expand on its original theme which was to present important practical aspects for using the squid as experimental animals. There are twenty two chapters instead of the original eight. The material in the original eight chapters has been completely revised. Since more than one method can be used for accomplishing a given task some duplication of methods was considered desirable in the various chapters. Thus the methodology can be chosen which is best suited for each reader s requirements. Each subject also contains a mini-review which can serve as an introduction to the various topics. Thus the volume is not just a laboratory manual but can also be used as an introduction to squid biology. The book is intended for laboratory technicians advanced undergraduate students graduate students researchers and all others who want to learn the purpose methods and techniques of using squid as experimental animals. This is the reason why the name has been changed to its present title. Preceding the chapters is a list of many of the abbreviations prefixes and suffixes used in this volume.