Andrew Wiles worked on Fermat's Last Theorem alone in his attic for 7 years and told nobody except his wife. The problem was 358 years old. Fermat scribbled in a margin in 1637 that he had a proof and no room to write it, and every mathematician since had failed. Wiles saw the statement in a library book at 10 years old. He never let it go. He was a Princeton professor when he started in 1986. He stopped publishing new work and released old results in pieces to hide the silence. He announced it in Cambridge in June 1993, over 3 lectures, revealing the target only at the end. Newspapers ran it worldwide. Then a referee found a gap. One step in the proof did not hold, and the error was fundamental. He spent 14 months trying to close it in public view, with the whole field watching. He was ready to quit. The fix arrived in September 1994. He has said he stared at it in disbelief for 20 minutes. The BBC filmed him describing that moment. He gets a few words out, then turns away from the camera in tears. He kept the greatest result of the century secret so nobody could take it.