This thesis is a study of SS-(No Suggestions) Dr. Ernst Kaltenbrunner, who, from January 30, 1943, to May 8, 1945, served as chief of the Security Police and Security Service of National Socialist Germany. This post was one of the highest in the Nazi repressive machinery and one of the most important in the Reich as a whole. The first chapter of this study is devoted to Kaltenbrunner's life from the time of his birth on October 3, 1903, until his appointment as chief of the Security Police on January 30, 1943. During this forty year period Kaltenbrunner, the son of a bourgeois lawyer, rose from law student to higher SS and police leader in Vienna. It was during these four decades that the interaction of the collapse of the Habsburg monarchy, the impoverishment of his parents, the tumult of the twenties, the depression, and other factors molded his character. During these years he first displayed the "bully-slave" nature which was later to become the dominant element in his character. It was also during the later years of this period that he joined the National Socialist Party and the SS. In fact, from 1932 to 1935 he rose from SS recruit to commander of the SS in Austria and was twice imprisoned for his Nazi activities by the Dollfuss-Schuschnigg regime. In 1938 he aided in bringing about the Anschluss. From 1938 to 1943 he was one of the leading SS and police leaders in Germany. Then, in January, 1943, he went to Berlin as head of the Reich Security Head Office. Chapter II is concerned with Kaltenbrunner's activities after his appointment as chief of the Security Police. It deals with his involvement in the "White Rose" affair, the "bullet" decree, the repression of the July 20 plot, the attempted destruction of the concentration camps in 1945, and the "final solution of the Jewish problem." Finally, Kaltenbrunner1s life from early 1945 until his execution on October l6, 1946, is examined in the last chapter of this study. In this part his trial before the International Military Tribunal, the case against him, his defense, and his death are described in detail. Lastly, an attempt is made to fathom the character of the man, to show how typical he was of the higher echelons of the SS and police leadership as a whole, and to relate these factors to the problem of totalitarianism in general.