Derby, Connecticut: Monarch Books, Inc, 1963. 160 pages. "A Dramatic Probe into the World's Most Preessing Problem: Millenium or Annihilation?" - from front cover. ISBN: 281AIB1051162.
Inscribed by the author inside front cover: "Boo! To Alva Rogers. Poul Anderson," with drawing of mushroom cloud. First edition (first printing). A near fine copy in illustrated wrappers (paperback).