Penguin Books Ltd, Harmondsworth, Middlesex, England Penguin Books Pty Ltd, Ringwood, Victoria, Australia
First published by Simon & Schuster 1959 First published in Britain by Bell 1961 Published in Penguin Books 1965
Copyright © Martin Gardner, 1959
Material previously published in Scientific American is copyright 1956, 1957, 1958 by Scientific American, Inc
Made and printed in Great Britain by Cox and Wyman Ltd, London, Reading, and Fakenham Set in Monotype Bembo
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