There is a tremendous mythology surrounding Fermat, and interest in Fermat is high because of Wiles' proof of "Fermat's last theorem." Fermat was undoubtedly a genius, but exactly what he did and didn't do will never be clear, because he wrote so little about his methods and his proofs. Mahoney's book comes as close as I think it's possible to come in figuring out what Fermat's mathematical interests and methods were, what he proved and what he didn't. Only high school math is required to read this book easily; the writing style is clear, and the structure of the book is well organized.Some readers may be disappointed to learn that Fermat's abilities were only human, and that he made a number of mistakes. But even a genius is entitled to be less than perfect, and the real Fermat is in many ways more interesting than the myth. I recommend this book to anyone curious about Fermat's mathematical abilities and achievements.