Sleuth is a classic deduction game designed by Sid Sackson and released as part of the 3M Gamettes line. Each play begins with a deck of 36 gem cards shuffled; one is secretly hidden while the rest are dealt to the players, with any leftovers placed face‑up in the center. This gives everyone immediate clues about what the missing gem cannot be. A second deck of 54 search cards each shows one or two elements (diamonds, pairs, blue opals, red pearls, etc.). Every player receives four of these cards face‑up. On your turn you pick one and ask an opponent how many gems of that type they hold. If the query is generic, like “pairs,” the opponent only states the count; if it’s specific, such as “red diamonds,” they announce the number and secretly show the cards to the asker. All players record the answers on a reference sheet, tracking both positive and negative information. At any moment you may gamble and name the hidden gem; a correct guess wins instantly, a wrong guess removes you from contention but you still answer others’ questions. The rules are straightforward, yet the mix of visible cards and mere counts creates a surprisingly deep mental puzzle that rewards a solid note‑taking system. Play time is 30‑45 minutes, for 3‑7 players, with a light weight (2.5/5), perfect for fans of logical deduction without heavyweight complexity.