The Marriage of Heaven and Hell is one of William Blake's prophetic books, a series of texts written in imitation of biblical books of prophesy, but expressing Blake's own intensely personal Romantic and revolutionary beliefs. Like his other books it was published as printed sheets from plates etched with both texts and illustrations. The plates were then colored by Blake and his wife Catherine.

The Marriage of Heaven and Hell is probably the most influential of Blake's works. Its vision of a dynamic relationship between a stable 'Heaven' and a dynamic 'Hell' has fascinated theologians, aestheticians and psychologists. It has also inspired many artists and musicians.

It was composed between 1790 and 1793, in the period of radical ferment immediately after the French Revolution.

The book describes the poet's visit to Hell, a device adapted by Blake from Dante's Inferno and Milton's Paradise Lost. However, Blake's conception of Hell is not as a place of punishment, but as a source of unrepressed energy. Blake's purpose is to create what he called a "memorable fancy" in order to reveal to his readers the repressive nature of conventional morality and institutional religion.

In the most famous part of the book, Blake reveals the Proverbs of Hell. These display a very different kind of wisdom from the Biblical Book of Proverbs. The diabolical proverbs are provocative and paradoxical. Their purpose is to energise thought. Several of Blake's proverbs have become famous:

"The road of excess leads to the palace of wisdom;
The tigers of wrath are wiser than the horses of instruction;
One law for the lion and ox is oppression"

Blake explains that,

"Without Contraries is no progression. Attraction and Repulsion,
Reason and energy, Love and Hate, are necessary to Human existence.
From these contraries spring what the religious call Good & Evil.
Good is the passive that obeys Reason. Evil is the active springing
from Energy."

During a visit to a "printing house in hell," Blake learns that diabolic printing is conducted with corrosives (that is by etching). This method helps to "cleanse the doors of perception." Blake promises to adopt this "infernal method" in his own works back on earth.

The book ends with a series of revolutionary prophesies and exhorations.

Blake's text has been interpreted in many ways. It certainly forms part of the revolutionary culture of the period. The references to the printing house suggest the underground radical printers producing revolutionary pamphlets at the time. Ink-blackened print workers were jokingly referred to as "printing devils," and revolutionary publications were regularly denounced from the pulpits as the work of the devil.

In contrast, the book has been interpreted as an anticipation of Freudian and Jungian models of the mind, illustrating a struggle between a repressive superego and an amoral id. It has also beeen interpreted as an anticipation of Nietzsche's theories about the difference between slave morality and master morality.