Leonard Trelawney Hobhouse is considered one of the founders of sociology as a discipline. His four books which form Principles of Sociology are published here together for the first time - representing a synthesis of the philosophical and scientific methods of social inquiry.Although very scarce, the study by Hobson and Ginsberg is still regarded as the most comprehensive account of Hobhouse's life and works. There is also a memoir by Hobson and a selection of Hobhouse's otherwise inaccessible writings.