The most mind-bending puzzles on the internet appear weekly in Oliver Roeder's "The Riddler" column. Presented by Nate Silver's FiveThirtyEight, this first-ever collection features the column's most popular problems, along with six never-before-published puzzles, all exploring the math implicit in everyday occurences. The simplest require a mere flash of insight, while the toughest involve deep applications of analysis and probability theory. Designed to appeal to a range of skill levels, The Riddler is a must-have for any math or puzzle enthusiast.