'The advantage of this book is to give both [the semi-classical and the full quantum] approaches, starting with the first, illustrated by several simple examples, and introducing progressively the second, clearly showing why it is essential for understanding certain phenomena … I believe that this challenge to present and to illustrate both approaches in a single book has been taken up successfully … I have the highest admiration for [the authors'] enthusiasm, their scientific rigor, their ability to give simple and precise physical explanations, and their quest to illuminate clearly the difficult points of the subject without oversimplification.' Claude Cohen-Tannoudji, from the Foreword

'… genuinely very impressive … every section has been lovingly crafted, the text is beautifully constructed and the theory explained more comprehensibly than almost any other text I could name. Each section is graced by numerous insightful … comments from the authors, giving the reader the impression of guidance by the hand of a teacher you can utterly trust. For a start, this book has possibly the finest, clearest and most extensive introduction to perturbative transitions I have seen … I am certain that this beautifully produced and written book, with an apparently faultless production, is destined to be a classic.' Professor David L. Andrews, University of East Anglia