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Managing Editor: Marla Patterson
Production Editor: Sue Rhodes Dodd
Book design: Robin Remaley
Cover design: Amy Spehar

Library of Congress Cataloging-in-Publication Data Available on Request

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transcribed in any form or by any means, electronic or mechanical, including photocopying and recording, without the prior written permission of the publisher.

1 2 3 4 5 07 06 05 04 03

ACKNOWLEDGMENTS

Ya. A. Gelfgat wrote Chapters 3 and 4. He wrote Chapters 1, 2, and 5 with M. Ya. Gelfgat, who wrote also Chapter 7. Yu. S. Lopatin wrote Chapter 6. Boris Volkovoy translated the Russian text written by Ya. A. Gelfgat and Yu. S. Lopatin. The authors express their great appreciation for Volkovoy's efforts in finding solutions for difficult-to-translate technical text. M. Ya. Gelfgat did the technical review of the English text.

The authors acknowledge the invaluable help of several prominent Russian drilling specialists in commenting, advising, and reviewing different book chapters and sections, namely:

Valeriy Petrovich Shumilov section on turbodrills in Chapter 2, especially "multistage turbine theory development"

Dmitry Fedorovich Baldenko section on positive displacement motors (PDM) in Chapter 2

Bairas Ibragimovich Abyzbaev section on electrodrills in Chapter 2 and section on electrodrills application in directional drilling in Chapter 4

Bronislav Vasilievich Baidyuk Chapter 3

Rudolf...