The second edition retains the basic structure and governing ideas of the first, but is content has been substantially changed to take account of new developments in the field and the experience with the book reported to us by teachers and students. The changes are of three kinds. (1) Statistical and quantitative materials in all chapters have been brought up to the latest possible date. These changes are reflected in the text as well as in table graphs. (2) Most of the chapters have been considerably rewritten to embody recent developments in sociological research and analysis to improve their organization and exposition. (3) Three new chapters have been introduced on alcohol, poverty and war and disarmament to deal with vital problems of contemporary society not included in the first edition.