First published in 1927, the original blurb of Psychology: Its Methods and Principles reads: "In this book psychology is presented as the science of adaptive behavior. The writers are convinced that the study of such behaviour provides a more effective introduction to psychological science than the study of consciousness as such. They are not committed, however, to the tenets of any particular psychological 'school'. They have utilized both behaviouristic and introspective material without attempting to distinguish between 'introspection' and 'verbal report'. Throughout the text stress is placed upon the scientific methods by means of which adaptive behaviour is investigated in the psychological laboratory." Today it can be read in its historical context. This book is a re-issue originally published in 1927. The language used and views portrayed are a reflection of its era and no offence is meant by the Publishers to any reader by this re-publication.