CLOSE TO CRITICAL. London: Victor Gollancz Ltd, 1966. Octavo, boards. First British (and first hardcover) edition. "Humans attempt to contact the alien inhabitants of the extremely inhospitable heavy gravity planet Tenebra. A scrupulously scientific adventure which hews closely to the author's earlier success, MISSION OF GRAVITY. The result is not quite as effective, though." - Pringle, The Ultimate Guide to Science Fiction, second edition (1995), p. 71. Anatomy of Wonder (2004) II-257. A fine copy in fine dust jacket with just a hint of tanning to spine panel and a small price sticker pasted over the publisher's price printed on the front flap. A sharp copy. (#148610).
No statement of printing.