This book is directed to three distinct audiences that may also enjoy some overlap: teachers of either probability or computer science looking for supplementary material for use in their classes, students in those classes looking for additional study examples, and aficionados of recreational mathematics looking for what I hope are entertaining and educational discussions of intriguing probability problems from
"real life." In my first book of probability problems, Duelling Idiots and Other Probability Puzzlers (Princeton University Press, 2000), the problems were mostly of a whimsical nature. Not always, but nearly so. In this book, the first test a problem had to pass to be included was to be practical, i.e., to be from some aspect of "everyday real life."