German was among the many languages Joseph Campbell read fluently; indeed, he studied at the University of Munich in the late 1920s.
The influence of German philosophy on 20th-century thought cannot be overestimated. Kant, Marx, Hegel, Nietzsche, Freud--these are just a few of the names that come to mind.
Campbell was particularly interested in the work of Arthur Schopenhauer and his emphasis on will. He also read deeply, and often quoted from, the work of Friedrich Nietzsche, who was also influenced by Schopenhauer.
One of the lesser-known philosophers (today) to whom Campbell was deeply indebted was Oswald Spengler, whose The Decline of the West detailed the theory that civilizations--including ours--rise and fall in a series of cycles. Further, as the title says, we are now in the "fall" stage.
This is from Stephen and Robin Larsen's biography of Campbell, A Fire in the Mind:
The Decline of the West was a brilliant if unconventional book, and an unusual purview of history and culture from ancient to modern times, from Chinese and Indian civilization through the classical cultures and into the contemporary West. Spengler's generalizations were sweeping but highly informed.
At the outset of his opus, Spengler declares that he is proceeding not by the painstaking methods of exact science, but by a series of intuitive analogies, often informed by mythological ideas. [It is easy to see the significance of this approach to Campbell's work. -J.B.] Some of his categories of cultural styles, such as the Magian, the Apollonian, the Faustian, have achieved historical quasi-respectability as metaphoric terms of reference for the greater patterns of culture which are manifested through time.
Next time: Anthropology