From the reviews:
"This book belongs to the collection Problem Books in Mathematics. Because of this choice, this book is not a course on Pells equation but a series of exercises which presents the theory of this equation . This book is certainly a good book for students who are courageous enough to try to solve many exercises; they can learn a lot this way. Moreover, this long collection of exercises presents a lot of examples and a great variety of methods." (Maurice Mignotte, Zentralblatt MATH, Vol. 1030, 2004)
"This is Barbeaus second book in the Springer Problem Books in Mathematics series . Brief hints are given at the end of each chapter and Answers and Solutions are given at the end of the book . All of the material in the book is aimed at undergraduate level. The book does provide a good source of exercises and interesting ideas for student projects, as well as giving a reasonably thorough account of the solutions, applications and generalisations of Pells Equation." (Peter G. Brown, The Australian Mathematical Society Gazette, Vol. 30 (4), 2003)
"The present book is described by its author as a focussed exercise book in algebra, and is aimed at both college students and talented sixth-formers, with the particular intention of providing training in the key skills of manipulating algebraic expressions judiciously, and with a sense of strategy. readers are encouraged to do much of the exploring for themselves through carefully guided examples . The book is full of interest, and largely succeeds in its aims." (Michael Ward, The Mathematical Gazette, Vol. 88 (512), 2004)
"Ed Barbeau has prepared a focused exercise book in algebra based on various aspects of Pells equation. The author does a wonderful job in preparing and motivating the reader . An array of interesting related problems, facts, and explorations are found here. This book is astepping stone towards any one of the several related areas of study, including diophantine analysis, diophantine approximation, algebraic number theory . It is perfectly suited for any first course in number theory." (Gary Walsh, SIAM Review, Vol. 46 (1), 2004)
"The authors book, as the title indicates, is primarily concerned with aspects of Pells equations . The book has nine chapters followed by extensive answers, comments and solutions to posed problems and explorations, a glossary of several pages, separate references to books and papers, and a brief index. would also be suitable for any person interested in number theory. The book reveals the enduring interest by mathematicians in Pells equation ." (George W. Grossman, Mathematical Reviews, 2004f)
"Barbeau develops the theory of Pells equation (a piece of quadratic form theory) entirely as a series of exercises. The books form recommends it for shepherding undergraduates to research, and is a good source for higher-degree analogs of Pells equation. Includes problem answers and solutions." (D.V. Feldman, CHOICE, December, 2003)
"Pells equation is an important topic of algebraic number theory that involves quadratic forms and the structure of rings of integers in algebraic number fields. The topic is motivated and developed through sections of exercises that allow students to recreate known theory and provide a focus for their algebraic practice. There are also several explorations that encourage readers to embark on their own research." (Zentralblatt für Didaktik der Mathematik, August, 2003)
"Pells equations are as old as mathematics, but the theory of these equations is a modern branch of mathematics development. This book is a curious exercise book, but it is much more. The exercises, explorations are well-chosen, showing the real nature of mathematical thinking . Without any special background you willenjoy the problems throwing you in the very heart of this science. Whoever you are you will find some beautiful, mind awakening problems in this book." (Lajos Pintér, Acta Scientiarum Mathematicarum, Vol. 74, 2008)
