Since beginning his seminal book Personality, a Psychological interpretation ", Gordon Allport has continued to review and develop his theory of personality. In this book, reiterates the basic principles in the light of recent research. This book is intelligible even to the uninitiated is studying psychology, without ceasing to retain the systematic character that distinguished the earlier work. Professor Allport examines eclectically modern theories of personality and the results of the investigation. This test takes almost exhaustive its meaning by the fact that the author in each acso, tries to show how far examined the contribution clearly fits the personality, conceived as a typical system in constant development.