Vintage Paperback Book, "Master of Life and Death", Robert Silverberg, "The Secret Visitors", James White, 1957, Ace Double #D-237. Paperback original (PBO), cover art by Emsh. Grades GD. Some cover wear, some edge wear, some corner wear and clipping, spine wear and small spine splits, some creasing, some small pages tears (nothing missing from text), pages and inside covers beginning to brown around the edges. Good reader copy or collection space filler.