"classic"

Title: Fermat's Enigma: The Epic Quest to Solve the World's Greatest Mathematical Problem (US)
Fermat's Last Theorem: The story of a riddle that confounded the world's greatest minds for 358 years (UK)

Author: Simon Singh

Short Description: The history of Fermat's Theorem, from the famous note "It is impossible to separate a cube into two cubes, or a fourth power into two fourth powers, or in general, any power higher than the second into two like powers. I have discovered a truly marvellous proof of this, which this margin is too narrow to contain." to the solution of the Taniyama-Shimura-Conjecture by Andrew Wiles.

By the way, the video Fermat's Last Theorem (1996) is based on the book.