Originally published : New York : Holt, Rinehart and Winston, 1967 ; London : Gollancz, 1978.
OBNB doesn't sell books, but you may be able to find a copy at one of these websites:
The gate of worlds by Robert Silverberg. ISBN 041704710X. Published by Magnum Books in 1980. Publication and catalogue information, links to buy online and reader comments.
