Solving the Pell Equation (CMS Books in Mathematics) - Tapa dura

From the reviews:

"‘Solving the Pell Equation’ is a ... monograph that offers encyclopedic in-depth coverage of its topic. ... The book is very well-written and filled with many interesting asides. ... As one of the book’s stated goals is to provide ‘a relatively gentle introduction for senior undergraduates,’ a much larger set of examples ... increase the number of students at every level who could profitably read this text. ... I highly recommend the book to anyone with an interest in Pell’s equation and its modern study." (Thomas Hagedorn, The Mathematical Association of America, July, 2009)

"This new book on the Pell equation, eagerly anticipated by the mathematical community and written by two active contributers to the field of computational number theory in general and to Pell’s equation in particular, exposes the ongoing interaction between modern computational number theory and practice in a way that is pleasant to read and to study, and that is readily accessible to conscientious undergraduate students. ... this book is highly recommended." (Robert Juricevic, Mathematical Reviews, Issue 2009 i)

Pell’s Equation is a very simple Diophantine equation that has been known to mathematicians for over 2000 years. Even today research involving this equation continues to be very active, as can be seen by the publication of at least 150 articles related to this equation over the past decade. However, very few modern books have been published on Pell’s Equation, and this will be the first to give a historical development of the equation, as well as to develop the necessary tools for solving the equation.

The authors provide a friendly introduction for advanced undergraduates to the delights of algebraic number theory via Pell’s Equation. The only prerequisites are a basic knowledge of elementary number theory and abstract algebra. There are also numerous references and notes for those who wish to follow up on various topics.