Imagine this: you are browsing used books in a bookstore hundreds of miles from home when you come across a copy of Moby Dick, which you remember reading as a child. You open it and find your own name on the inside cover. What are the chances? This is the question we ask ourselves upon encountering seemingly impossible coincidences, like the woman who won the lottery four times. But from clairvoyants to financial markets, and from unique scientific discoveries to DNA evidence, if there is any likelihood that something could happen, no matter how small, it is bound to happen to someone at some time. Coupling lively anecdotes with the principles of probability, Joseph Mazur balances the fun of a great coincidence with the logical thinking of a mathematician