This book seeks to untangle the cosmological treatise on the relationship between the physical and spiritual universe found in Edgar Allan Poe’s Eureka, the work he considered to be his magnum opus but which was also largely ignored by scholars until it caught the attention of physicists, astronomers, and other scientists in the 1990s. Since its publication in 1848, Eureka has confused readers and stirred controversy among critics who couldn’t decide whether or not Poe was serious, joking, or mad in writing the work, which he initially delivered as a lecture and then published featuring both the subtitles “A Prose Poem” and “An Essay on the Material and Spiritual Universe.” Within it, he explored epistemology, theology, philosophy, physics, astronomy, cosmology, poetry, God, justice, and the problem of evil and laid out the basic principles of what would later be known as Big Bang Cosmology, Chaos Theory, Relativity Theory, and biological evolution. This volume is the first to demonstrate how all of the diverse pieces of the work fit together, including how it could be called both a prose poem and an essay, how Poe could be serious about his argument without losing his sense of humor, and how Poe’s rejection of reductionism presents a helpful model for twenty-first century inquiry.