The Sapphire Conference

First published in the United States in 1959. The copyright is assigned to Peter Graaf in 1959. Price from seller's description on AbeBooks. Last page is unnumbered. Though author's name credited by OCLC and LCCN entries as John Christopher, a cover image shows Peter Graaf. The title page of the copy on scanned images says Peter Graaf. See also abebooks. LCCN ID from copyright page, the actual one is {{LCCN|59009370}}.