This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book addresses a central problem of interpretation faced by biographers seeking to understand the decisionmaking processes of political leaders. It deals with the relevance of psychoanalytic theory to the biographer's work. The book focuses on the broader issue of the character and psychological suitability of candidates for the presidency, which has received increasing attention in the past few decades. It discusses the importance of a president's "style" in structuring and managing the policymaking process. The book presents a more detailed analysis of different types of presidential style and of the way in which personal styles of different presidents influence how they structure and manage the policymaking process. It explores three personality variables among presidents since Franklin D. Roosevelt, and it is suggested how these personality differences help to explain their preferences for different management models.