Eureka is a long prose work that Poe called a prose poem. In it he sets out his own vision of the universe, from its origin in a single primal unity to its development, and perhaps its eventual return. He mixes science, philosophy and imagination, drawing on the astronomy of his day while following his own intuitions. Scientists have judged much of it wrong, yet it contains some striking guesses and shows his ambition as a thinker. It is an unusual work, the last major piece he published, and it offers a view of his mind beyond the tales of horror.