Preface to the Revised Edition In addition to the acknowledgments above,my former students Li Ping,Shi Xiaohong,and Yasunaga Suzuki provided the sounding board for ideas on the revised edition hen taking my graduate qua ntum me chanics course at the University of Hawaii during the spring of 1992.Suzuki provided the initial translation from Japanese of Supplement I as a course term paper.Dr.Andy Acker provided me with computer graphic assis- tance.The Department of Phy sics and Astronomy and particularly the High Energy Physics Group of the University of Hawai at Manoa provided again both the facilities and a conducive atmosphere for me to carry out my editorial task.Finally I wish to express my gratitude to Physics (and onsoring)Senior Editor,Stuart Johnson,and his Editorial Assistant, Duggan,as well as Senior Production Coordinator Amy Willcut of Addison-Wesley for their encouragement and optimism that the revised edition will indeed materialize. San Fu TUAN Honolulu,Hawaii