This book about Psychological Relativity Theory , which published in Arabic in 1991, but it is the first time to publish in English .Author criticized the traditional studies and methods in psychology, we have thousands of studies in psychology lead to nothing, Complex statistics are not the suitable tools for analyzing the data and information in personality . the author present two methods to studying personality depend upon psychological relativity theory.author think this theory is very important to develop psychology especially personality ,social psychology and cognitive psychology.