All rights reserved.

A member of the Reed Elsevier group

Digital Press is an imprint of Butterworth Heinemann.

All trademarks found herein are property of their respective owners.No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher.

Recognizing the importance of preserving what has been written, Elsevier Science prints its books on acid-free paper whenever possible.

Library of Congress Cataloging-in-Publication Data

British Library Cataloguing-in-Publication Data

A catalogue record for this book is available from the British Library.

The publisher offers special discounts on bulk orders of this book. For information, please contact:

Manager of Special Sales
Butterworth Heinemann
225 Wildwood Avenue
Woburn, MA 01801-2041
Tel: 781-904-2500
Fax: 781-904-2620

For information on all Butterworth Heinemann publications available, contact our World Wide Web home page at: http://www.digitalpress.com or http://www.bh.com.

10 9 8 7 6 5 4 3 2 1

Printed in the United States of America

To Deborah, with love, for many reasons.