I have a DVD of Darren Brown. He reads allot of body language in his tricks and is a complete master at reading it. I learnt allot just by watching his DVD. He is so good at using it he can cash in loosing tickets at bookies just by confidently presenting the tickets as winning ones. (needless to say he is very good with the girls as well - although he may of put those bits in his video to make himself look cool...
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After watching his DVD, I found that I cold read people allot better - detecting lies was the best one and also detecting when a girl fancies you. It's easy when you know what to look for.