In 1946, Simon and Schuster published Joshua Loth Liebman's bestselling book Peace of Mind. His self-help manual explained how psychiatry and religion together could help achieve emotional and spiritual maturity, ultimately leading to individual happiness. Liebman theorized that if individuals were happy, it would then have a profound effect on the social, political, and economic problems of the day, believing that "happy people created a happy society." Peace of Mind remained on the bestseller list for three years, earned accolades from clergy and psychiatrists, and reached readers on six continents. In depth analysis of its place within religious, psychological, and self-help cultures alongside readers' use and interpretation provides insight into its contributions to those cultures. This assessment proves that Peace of Mind marked an important point in the definition and contribution to happiness in the immediate postwar era.