Alien Planet (Ace, F-257)

First paperback edition (1963) with wonderful Emsh cover art. First published in hardcover the previous year, this novel is an expansion of "A Voice Across the Years," a story first published in Amazing Stories Quarterly, Winter 1932. Two Earthmen [Merrick Wells and Alvin Schierstedt] meet Ashembe of Murashema, who has come from beyond the stars on an urgent mission.