The importance of the ?eld of atomic physics to modern technology cannot be overemphasized. Atomic physics served as a major impetus to the development of the quantum theory of matter in the early part of the twentieth century and, due to the availability of the laser as a laboratory tool, it has taken us into the twen- ?rst century with an abundance of new and exciting phenomena to understand. Our intention in writing this book is to provide a foundation for students to begin researchinmodernatomicphysics. Asthetitleimplies,itisnot,norwasitintended to be, an all-inclusive tome covering every aspect of atomic physics. Any specialized textbook necessarily re?ects the predilection of the authors toward certain aspects of the subject. This one is no exception. It re?ects our - lief that a thorough understanding of the unique properties of the hydrogen atom is essential to an understanding of atomic physics. It also re?ects our fasci- tion with the distinguished position that Mother Nature has bestowed on the pure Coulomb and Newtonian potentials, and thus hydrogen atoms and Keplerian - bits. Therefore, we have devoted a large portion of this book to the hydrogen atom toemphasizethisdistinctiveness. Weattempttostresstheuniquenessoftheattr- tive 1/r potential without delving into group theory. It is our belief that, once an understanding of the hydrogen atom is achieved, the properties of multielectron atoms can be understood as departures from hydrogenic properties.

The eleventhAdvancedS tudyInstitute(ASI) on Techniquesand Con­ ceptsof High Energy Physics marks thetransitionfrom anextraordinary centuryof scienceto one thatwill surely bring wonderswe can scarcely imagine.It also marks a transitionfrom its founder,theinimitableTom Ferbel,to its newdirectors . We are honoredto have beenasked to con­ tinue the venerabletraditionthat Tom established. The school is his distinctivecreation , and will always bearhis mark. The 2000 meetingwas held at the Hotel on the Cay in St. Croix. It is an ideal location: sufficientlysecluded to inspire a vigorous but informal intellectualatmosphere,yet closeenough to the main island to afford opportunitiesto mingle with the locals and partakeof their hospitality.Altogether 76 physicistsboth young, and not so young, par­ ticipatedfrom 18 count r ies . Forthe first time, this meetingattract ed a substantialnumber of studentsfrom EasternEurope, all of whom were warmly welcomed.The bulk of thefinancialsupportfor themeetingwas providedby the ScientificAffairs Division of the North Atlantic Treaty Organization(NATO). The ASI was co-sponsoredby the U .S. Depart­ ment of Energy (DOE) , by the Fermi National Ac celeratorLaboratory (Fermilab), by the U.S . NationalS cien ceFoundation(NSF ), the Univer­ sity of Rochester , Florida State University (FSU) and the Institutefor Theoreticaland ExperimentalPhysics (ITEP , Moscow). As is the tradition , the scientificprogramwas designedfor advanced graduatestudentsand recentPhD recipientsin experimentalparticle physics. The present volume covers topics that updateand comple­ ment those published (by Plenum and Kluw er) for the first ten ASIs. The materi al in this volume shou ld be of interest to a wide audience of physicists.