As a contemporary historical document, Klemperer's diaries are unique and indispensable. In the future, one will not be able to form a picture of the daily reality of National Socialism without knowing these diaries. Klemperer's diaries will henceforth be among the enduring testimonies of German history and culture. Here, history itself has, in a sense, co-written and imparted something of its overwhelming power to the written word. This is not least the reason for the unexpected impact that has been observed since the publication of these records. It is an extraordinary work, likely the most significant, alongside Anne Frank's diary, that has survived from that dark era. The diaries demonstrate an exceptional power of observation, linguistic mastery, and human greatness.