I always have difficulty with logic puzzles. Usually, I miss making inferences that really make the puzzle's solution flow out. Are there any good books/resources that train people on logic puzzles? (I moved this from the brain teaser forum) The kind of puzzle I'm talking about would go something like this: Five bidders at an auction are hoping to secure a particularly nice piece of china. From the information given, can you work out where each is standing in the room, his or her bid, and the covert method of signaling each uses to indicate their bid to the auctioneer? 1. The initial bid of $200 was made by nodding, but not by the bidder in the middle of hte room. 2. Mr. Lott raised it to $225, but not by raising his finger; the bid made by that means was lower than Mr. Gowing's. 3. Mrs. Gavell didn't take the price to $250; the person standing on the right raised the bid to $275. 4. Mrs. Nock touched her ear to register her bid, but it was lower than that of the person sitting in the front row. 5. The bidder standing to the left signaled a bid by raising his or her programme slightly. 6. Mr. Sayle was standing in the back of the auction room. Bidders: Mrs. Gavell, Mr. Gowing, Mr. Lott, Mrs. Nock, Mr. Sayle Signal Method: Nodding, raising finger, raising programme, Touching ear, winking Bid: 200, 225, 250, 275, 300 Position: Front row, middle, standing at back, standing left, standing right All of the problems I'm referring to are of this format. I tried using the grid that they give in the book, but that doesn't help. Is there a systematic way to diagram and solve these without a grid? Thanks.