Karl Jaspers (1883–1969), a German philosopher, was, for most of his career, professor of philosophy at the University of Heidelberg. After the end of World War II and the collapse of the Nazi régime, he accepted a professorship at the University of Basel in Switzerland, where he completed his career. He was a special target of the Nazis, largely because his wife was Jewish. They were, however, allowed to live in seclusion in Heidelberg throughout the period of the Nazi rule.

It is interesting that Jaspers came to philosophy from medicine and psychiatry. Before medicine, he had studied law at the universities of Heidelberg and Munich in 1901 and 1902. For the next six years, he studied medicine at the universities of Berlin, Göttingen and Heidelberg. In 1908, he passed the state exam to practice medicine and in February 1909, he was registered as a doctor.

Jaspers could very well have made his career in psychiatry. As it was he wrote a general book, Allgemeine Psychopathologie (1913), which went through several editions and was importantly influential. This background is surely significant for the nature of his first major philosophical work, namely the Psychologie der Weltanschauungen (1919), which, however, was not a clinical study of personalities, although he did this for such figures as Strindberg, Van Gogh and Nietzsche, but was rather a typological study of possible kinds of world view. One unsolved problem for the researcher is to define Jaspers's relation to Freud. In his writings, Jaspers makes relatively sparse references to Freud's work, and most of them are on the derogatory side. It seems likely that Jaspers never made a careful study of Freud and was not attracted to his ideas. Perhaps Freud struck him as too biologically oriented.

In the 1920s, Jaspers was one of the few most prominent personalities in the University of Heidelberg community. He particularly interested sociologists because he was a special admirer and had been a close personal friend of Max Weber.

Jaspers's place in philosophy is linked to the concept of existentialism. Perhaps his best-known book is Reason and Existenz (1935). It is notable that the translator and publisher retained the German form of the word Existenz, which Jaspers treated as definitely a technical term.