Philosophy of the Unconscious: Speculative Results According to the Induction Method of the Physical Sciences is an 1869 book by the philosopher Eduard von Hartmann. The culmination of the speculations and findings of German romantic philosophy in the first two-thirds of the 19th century, Philosophy of the Unconscious became famous. By 1882, it had appeared in nine editions. A three volume English translation appeared in 1884. The English translation is more than 1100 pages long. The work influenced Sigmund Freud's and Carl Jung's theories of the unconscious.

Karl Robert Eduard von Hartmann was a German philosopher, independent scholar and author of Philosophy of the Unconscious (1869). His notable ideas include the theory of the Unconscious and a pessimistic interpretation of the "best of all possible worlds" concept in metaphysics.