Stated first printing, verified paperback original by ISFDB. Tight, flat, square, sharp book. Pages toned. Owner's marks on the inside front wrapper. Spine reinforced with librarian's tape. Wraps creased. 

And they named the planet Sparta. Long ago the humans had settled this planet - too long ago for anyone to remember.
Slowly the civilization had developed, and now it was complete. A civilization of war and violence. A civilization of crude pleasures. A civilization in which human beings were produced by birth machines - and women were unknown.
It was a civilization whose terrible secret only the doctor-priests knew - a secret that a desperate man named Brasidus decided to penetrate, even at the risk of something worse than death....