Pierre de Fermat wrote:
I have a truly marvelous proof of this proposition which this margin is too narrow to contain.
His proof of the theorem was never found, so it became know as Fermat’s Last Theorem, which is:
If an integer n is greater than 2, then the equation an + bn = cn has no solutions in non-zero integers a, b, and c.
Simon Singh directed :
Simon Singh then wrote an excellent book about it, too, called The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography and Big Bang: The Origin of the Universe. I highly recommend anything he’s written: they’re easy reads for the laymen packed full of anecdotes, history, and explanations.. Singh is a superb science author who has also written
Fermat’s Last Theorem was proven in the 1990s and it ain’t straight-forward. Here’s the original paper (PDF) proving it: The Proof of Fermat’s Last Theorem by R. Taylor and A.Wiles.