It's not elementary, but you will need Holmes's famed powers of deduction to solve these crafty puzzles. Here's how it goes: at the end of each conundrum, you'll find at least one condition--and sometimes more--that the solution must meet. For example, here's the first, relatively simple problem: Mr. Scott, his sister, his son, and his daughter are tennis players. Which one of the four is the best player? Did you figure out that Mr. Scott's sister had to be the same age as his children? A few of the puzzles demand a basic knowledge of algebra, and others feature drawings or diagrams.