Sleuth is a classic detective game where skillful questioning of opponents is needed as each player gathers and records evidence. The winner must use his powers of deduction and logic to identify the missing gem. The simplicity of the rules and the cards belies the depth of this game. In some cases you see cards, in other cases you only hear the number of cards that an opponent holds. The notation system you devise must be both flexible and reliable, as you record both positive and negative answers; eliminate possibilities one by one; and arrive at the correct solution to the mystery!