Night of Light by Philip Jose Farmer
Paperback. Condition: Very Good. 1977. Berkley. Third Printing.
Every seven years, the placid planet of Dante's Joy becomes a waking nightmare of death, deformity, and madness. To escape, the populace has the choice of Sleeping--lying drugged in their tomblike houses--or taking the Chance--staying awake and going abroad while their world goes berserk. They become what their innermost longings dictate, whether it be a beast locked in the vilest bowels of depravity, or a supreme being raised to the flowering serenity of truth and light. Thousands are mutilated, killed, transformed into monstrous things. John Carmody, a conscienceless exile from Earth, arrogantly chooses to take the Chance. Reeling, shrieking his fear and despair, Carmody confronts the Night of Light, the unknown and unknowable..