Originally titled Vala, The Four Zoas was left unfinished at Blake's death and was first published in 1893 in a printing edited by William Butler Yeats and Edwin Ellis. The incomplete manuscript had been given to John Linnell, the publisher who commissioned Blake to do Illustrations of the Book of Job. The literary critic Northrup Frye called The Four Zoas "the greatest abortive masterpiece in English literature."

For The Four Zoas, Blake grafted mythologies from several of his earlier "minor prophecies," later utilizing some of the same material for his Milton and Jerusalem.

Most of the original drawings for The Four Zoas were in pencil; a few had color or ink added.

Influenced at least in structure by Edward Young's Night Thoughts on Death, which Blake had illustrated the year before, this work is likewise divided into nine "Nights" and originally carried the subtitle "A Dream of Nine Nights." The "zoas" (the Greek word for "beasts") are Blake's four-part universe: Eden, Beulah, and the realms of Urizen and Ulro. This lengthy symbolic poem--Blake's answer to Milton's Paradise Lost-- was his attempt to incorporate his many myths into a single work.

In a letter to Thomas Butts in 1803, Blake said of this work, "I have . . . composed an immense number of verses on One Grand Theme, Similar to Homer's Iliad or Milton's Paradise Lost, the Persons & Machinery intirely [sic] new to the Inhabitants of Earth. . . . I have written this Poem from immediate Dictation, twelve or sometimes twenty and thirty lines at a time, without Premeditation & even against my Will. . . ."

Shown here are two plates from The Four Zoas, with Blake's mythological characters. . On the left, the plate captioned "Urizen weakens Orc by stretching him on the Tree of Mystery," emphasizes Orc's Christ-like identity ; while the large plate on the right shows Enitharmon confronted by Orc in the shape of a serpent, an indication of the complex and shifting nature of Blake's mythological world.