The Kybalion is a book originally published in 1908 by "Three Initiates" (often identified as the New Thought pioneer William Walker Atkinson, 1862–1932) that purports to convey the teachings of Hermes Trismegistus.
While it shares with ancient and medieval Hermetic texts a number of traits such as philosophical mentalism, the concept of 'as above, so below', and the idea that everything consists of gendered polar opposites, as a whole it is more indebted to the ideas of modern occultist authors, especially those of the New Thought movement to which Atkinson belonged. A modern Hermetic tract, it has been widely influential in New Age circles since the twentieth century.