Second New English Library printing.
192 pages.
Cover by Gerald Grace.
Introduction by Auberon Waugh.
First published as a three part serial in Analog Science Fiction/Science Fact, April, May & June 1972, Vol LXXXIX No. 2/3/4.
First hard back published by Faber and Faber in the UK with this title and by Putnam in the US as "Tunnel Through the Deeps", (1972).
Hard back by The Science Fiction Book Club (UK), (1973).
First paperback (in English), by Berkley Medallion, in the US as "Tunnel Through the Deeps" (1974) and by New English Library (1976), with this title.