The Book of Thel is a poem by William Blake

William Blake

William Blake was an English poet, painter, and printmaker. Largely unrecognised during his lifetime, Blake is now considered a seminal figure in the history of both the poetry and visual arts of the Romantic Age...

, dated 1789 and probably worked on in the period 1788 to 1790.
It is illustrated by his own plates, and is relatively short and easy to understand, compared to his later prophetic books

William Blake's prophetic books

The prophetic books of the English poet and artist William Blake are a series of difficult and obscure poetic works. While Blake worked as a commercial illustrator, these books were ones that he produced, with his own engravings, as an extended and largely private project...

. The metre is a fourteen-syllable line. It was preceded by Tiriel

Tiriel (Blake)

Tiriel is a narrative poem by William Blake, written c.1789. Considered the first of his prophetic books, it is also the first poem in which Blake used free septenaries, which he would go on to use in much of his later verse...

, which Blake left in manuscript. A few lines from Tiriel were incorporated into The Book of Thel. Most of the poem is in unrhymed verse.

This book consists of eight plates executed in illuminated printing.