Ace (F-412; 1st edition) 1966 paperback. Cover by Gray Morrow, frontispiece by Jack Gaughan, 159 pages, 40 cent cover price. Condition is VG/VG+: tight and almost square; spine is flat with a line down the length; mild uniform age tanning (darker on insides of covers); light to moderate overall wear - mainly as faint line next to spine and some finger-creases at left of front cover, 2" fold-trace at bottom left of back cover No stamps, marks or writing.

Philip Jose Farmer's The Gates of Creation. This is 2nd in his "WORLD OF TIERS" series.
[the flap copy from another edtion since the blurb for this gives little context]:
In the first book, Robert Wolff of earth opened a door to other universes, and found himself growing young. It turns out he was the Lord of one of these universes - who had lost his memory (or had it wiped out) and was re-educated as an Earthman. His real name/identity was Jadawin.
The Lords contested against each other in a sort of game. The Gates of Creation begins with the abduction of Chryseis - the woman Wolff/Jadawin loved - by his father, Urizen. This was the opening move in one of these "games." The only way to rescue her was to find the portal to his father's universe and bring her back. But the portal was difficult to locate, and even if the quest succeeded, the traps his sire had laid for him could easily turn Jadawin's triumph into tragedy. Urizen had many children; Wolff/Jadawin encounters them in his quest.