vi Preface she (he)will marvel at the simplicity and beauty of quan and tum mechanics,and at the same time its subtle and far-reaching conse the- One of the main aims of this book is to try to convey this sense of wonder to young students who are starting to appreciate the beauty of physics. of This book is,in fact,meant to be an introductory textbook on quan ph tum mechanics:it should be adequate for those who are learning it for the first time,as well as for slightly more advanced students.Standard courses on classical physics,including classical mechanics,electromag- netism,statistical mechanics and thermodynamics,plus basic mathe matics,should provide a sufficient background. to At the same time.how er we bop that this book with its many and the dive e subjects discussed,will be rcher and teachers alike Let us illustrate ome of the innovative feat s of this book.We took pe 0g10 has much logical clarity an methods are introduced gradually,and eac them is We start,in from the very basic concepts illustrated by elementary applications and move on to more structural issues such as symmetry,statistics,and formal aspects of quantum mechanics,and then explore several standard approximation methods.Various applications of physical interest are then discussed.taking full advantage of the artillery we have armed ourselves with. As far as the content goes,for the most part,it is fairly standard, even though some of the discussions in the main text,e.g.in Chap- ter 12(systems with general time-dependent Hamiltonians),in Chapter 13 (metastable states),and in Chapter 15(atoms),and several topics treated in Supplements(Chapter 20).may often not be found in a stan dard texthook At the end of each chapter,there are a mumber of problems to be solved analvticallv to be solved by 。to both typ prov ided in form s(analy The in self-explanatory expos as an e mentary guide to the Mathematica commands u so that they should be easily usable even by those who are seing a Mathematica program for the first time.The reader is encouraged to run the program, enjoy obeerving how the wave functions evolve,for example,modify and extend the problems as she (he)pleases,try to improve the precision of the calculation,etc.(Here are practical tips for the beginner:first, carefully read the ReadmeFirst file before starting;second,make a copy of each nb file before proceeding,and keep the original intact.Use a copy,when actually running the program,and making modifications