"First published in 1980 by The Viking Press" stated on the copyright page.
The copyright page contains the complete Library of Congress Cataloging in Publication Data including the ISBN (0-670-41755-6), and the LCCN (79-56269).
Month of publication from the code "0980" printed on the front flap of the dustjacket. Date confirmed by the listing in Locus #238 (October 1980).
"Jacket design by Mel Brofman" printed on the back flap of the dustjacket.