Fermat’s Last Theorem for Amateurs

From the reviews:

MATHEMATICAL REVIEWS

"The history of elementary approaches to Fermat is very rich indeed, and Ribenboim has arranged these approaches in a way that makes them accessible to interested readers without extensive mathematical backgrounds…both readable and fairly comprehensive. This book would likely be of great interest to an enthusiastic undergraduate with a basic knowledge of rings and fields. In addition to describing the history of one of the great problems in number theory, the book provides a gentle and well-motivated introduction to some important ideas in modern number theory…any reader who spends a few hours with this book is guaranteed to learn something new and interesting about Fermat’s last theorem."