Pelicans ISBN 0 14 02.1900 5 - Practical Thinking 4 ways to be right; 5 ways to be wrong; 5 ways to understand

Penguin Books Ltd, Harmondsworth, Middlesex, England Penguin Books Inc, 7110 Ambassador Road, Baltimore, Maryland 21207, U.S.A. Penguin Books Australia Ltd, Ringwood, Victoria, Australia Penguin Books Canada Ltd, 41 Steelcase Road West, Markham, Ontario, Canada Penguin Books (N.Z.) Ltd, 182-190 Wairau Road, Auckland 10, New Zealand

First published by Jonathan Cape 1971 Published in Pelican Books 1976 Copyright © European Services Ltd, 1971 Illustrations copyright © Jonathan Cape Ltd, 1971

Made and printed in Great Britain by Cox & Wyman Ltd, London, Reading and Fakenham Set in Monotype Times

This book is sold subject to the condition that it shall not, by way of trade or otherwise, be lent, re-sold, hired out, or otherwise circulated without the publisher’s prior consent in any form of binding or cover other than that in which it is published and without a similar condition including this condition being imposed on the subsequent purchaser