We want to figure out who will win an election, if the stock market will crash, or if a suspect definitely committed a crime. The odds are not in our favor, but thankfully, there is hope. As Ian Stewart reveals, mathematics has given us some of the tools we need to better manage the uncertainty that pervades our lives. From medical research to figuring out how to win Let's Make a Deal, Stewart offers a satisfying tour of what we can know, and what we never will.