The book takes its name from the character Urizen in Blake's mythology, who represents alienated reason as the source of oppression.
The book describes Urizen as the "primeaval priest" and narrates how he became separated from the other Eternals to create his own alienated and enslaving realm of religious dogma.
Los and Enitharmon create a space within Urizen's fallen universe to give birth to their son Orc, the spirit of revolution and freedom.
Urizen's first four sons are Thiriel, Utha, Grodna and Fuzon (respectively elemental Air, Water, Earth, Fire, according to Chapter VIII).
In all these books, Blake completed their design composition, their printing and colouring, and their sales from that house.
Let each chuse one habitation: His ancient infinite mansion: One command, one joy, one desire, One curse, one weight, one measure One King, one God, one Law.
Orc's infant cries awaken Urizen, who begins to survey and measure the world he has created.
In contemplating himself, he is able to discover sins and records them in a book of brass that are a combination of Newton, the laws of Moses, and deism that force uniformity.
In the Newtonian belief the material universe is connected through an unconscious power which, in turn, characterises imagination and intellect as accidental aspects that result from this.
This early version of a "survival of the fittest" universe is connected to a fallen world of tyranny and murder in Blake's view.
[16] The poem portrays Orc and his three-stage cycle, whose stages are connected to historical events, although the latter are removed in The Four Zoas.