"De Moivre wrote a book on probability theory, The Doctrine of Chances, said to have been prized by gamblers. It is reported in all seriousness that de Moivre correctly predicted the day of his own death. Noting that he was sleeping 15 minutes longer each day, De Moivre surmised that he would die on the day he would sleep for 24 hours. A simple mathematical calculation quickly yielded the date, 27 November 1754. He did indeed die on that day."