In addition to our author, we would like to thank Larry B. Kling, Vice President, Editorial, for his overall direction; Pam Weston, Publisher, for setting the quality standards for production integrity and managing the publication to completion; Michael Reynolds, Managing Editor, for project management; Mel Friedman, Lead Mathematics Editor, for technical review; Weymouth Design, for designing our cover; and S4Carlisle Publishing Services, for typesetting this edition. Back cover photo by Eric L. Miller.