I feel like the Harrington books are almost required reading for tourney players. The 3rd book in the series is a workbook filled with poker puzzles. I like the way Harrington has constructed these books in a way that teaches you how to think about poker situations. He just doesn't tell you "do this or do that" but instead what you should be thinking about in similar situations. It reminds me of the way bobby fisher presents his book bobby fisher teaches chess. If you are interested in upping your tourney game, I would pick these up. I paid 30 bucks each when I got them many years ago, so $40 for all three books is a steal! GLWS
Caro's book of poker tells is also interesting, but I put much less stock in physical tells since they can be manipulated by players who I consider "actors". Still a fun read, and almost free at these prices, since the Harrington books are easy worth 20 bucks each.