French mathematician Pierre de Fermat scribbled this short proof into the margins of a book in 1637: x^n + y^n = z^n has no nonzero solution when n>2. This became known as Fermat's Last Theorem. Since Fermat conjectured it, many mathematicians worldwide have tried to write a proof for it. It remained unsolved for more than 300 years before Andrew Wiles solved it in 1993. Wiles devoted his entire career to this singular theorem. Before him, the French mathematician Sophie Germain made significant progress toward the solution.