The first two chapters provide general background information on the phylum mollusca; classification, general organization, abundance, distribution, size and diversity are all covered. The values of molluscan diversity are explained bringing out their importance as objects of aesthetic, commercial, food and biomedical nature and role in marine biodeterioration. The references at the end of the chapter would provide additional information and help in further research. Thus the format of the book has been so devised to facilitate both a beginner and also a serious worker with some knowledge of mollusca.
Chapter 3 deals with the systematic account of Polyplacophora and Gastropoda consisting of as many as 530 species belonging to 80 families. Under each class and family and some subfamilies important diagnostic characters are given. Each species is described giving salient shell characters and also illustrated so as to facilitate easy identification. Based on the collections available and also literature records, distribution of each species in India and elsewhere given. When a species is known to occur at many localities only the name of state is mentioned. Wherever possible additional information on the status, habitat etc. of the species are indicated.