This new English translation and 100th anniversary annotated edition of Psychodiagnostics, the only book published by Hermann Rorschach, showcases Rorschach’s empiricism and the wide-ranging flexibility of his thinking – and thus helps us to understand why his iconic inkblot test has survived for a century and is still being used around the world, with the support of a strong evidence base. The expert translation team have collaborated closely to create an accessible rendition of Hermann Rorschach’s presentation of the inkblot test that resulted from his empirical research experiments. Also included in this edition is the case study lecture on new developments in the test that Rorschach gave to the Swiss Psychoanalytic Society in 1922, just six weeks before his premature death. His book and the lecture are each accompanied by annotations for the first time, looking backward to the sources of Rorschach’s terminology and also forward to how the test is used today. Drawings and photographs from the Rorschach Archive as well as introductory chapters on the history of the translation and the creation of Psychodiagnostics bring the story of this important figure and his work to life. This volume is essential reading for both historians and contemporary users of the inkblot test and anyone interested in exploring personality testing.