Is there a scientific way to assess the validity of generalizations about historical events? Can we test psychological hypotheses about human behavior? In this book the author describes how the emerging field of historiometry provides such tests by applying quantitative analyses to historical data about representative people and events. The author presents an overview of historiometry, explaining how it is practised and how useful it can be to historians, psychologists, and other social scientists. He discusses the methodology of historiometry - formulating the basic questions of a study, deciding what information is necessary, and analyzing the information so as to assess the original hypothesis. He then shows how historiometry has expanded our scientific understanding of such key phenomena as genius, creativity, leadership, and aggression. By scrutinizing the personal papers, biographies, and creative output of historical figures ranging from composers, writers, and scientists to American presidents, European monarchs, and generals, practitioners of historiometry can illuminate many variables affecting human personality and achievement. Throughout the book, Simonton provides examples of the way that historiometry offers insights into such areas as the degree to which attitudes toward politicians are influenced by specific persuasion techniques, the effect of economic and political conditions on the authoritarian personality, and the impact of genetic endowment, birth order, family background, and formal education on personality development.