Notes: Price on front flap of Archive.org copy; only copyrighted to Gatland on copyright page, which also says "First published in Great Britain under the title The Frontiers of Knowledge by Allan Wingate (Publishers) Ltd." The acknowledgements, written by Gatland, say "My especial thanks are due to Derek D. Dempster, who joined me in writing part of the manuscript of the first edition of this book (originally published by Allan Wingate in 1957 under the title, The Inhabited Universe) when pressing commitments related to aviation prevented me from completing the work on time; also for his introduction to the person, and work, of Dr. Rolf Alexander."