An eleven year old George Kennan began keeping a diary on January 1, 1916. At the very start of the diary he wrote “In this simple, little book, A record of the day I cast; So I afterwards may look back upon my happy past” (684). Due to Kennan’s remarkably lengthy and prolific career as a policymaker, diplomat, and scholar, as well as the undeniable impact he has had on the direction of American foreign policy during the Cold War, historians have long been attracted to studying his thoughts and actions. No one could ever plausibly claim that Kennan has been ‘understudied’ and his two volumes of memoirs also offered many personal insights into his inner thoughts. However, with the publication of Frank Costigliola’s edited collection of Kennan’s diaries from the period between 1916 and 2004, there is little doubt that scholars will continue to be fascinated by the complexities of Kennan’s life and career. It is a life that was certainly not simple and, despite all of his accomplishments and honors, the diaries make it abundantly clear that happiness was never Kennan’s dominant mood.