I once read The Definitive Book of Body Language. Body language is an interesting topic, and you can Google a lot of articles about it. I think the most interesting thing I've read is how peoples' testosterone levels (male hormones) were raised after test subjects took imposing/dominating poses, and their levels were even lowered when they were placed in submissive poses. Now research suggests that people are capable of changing their hormone levels using body language, and if one wanted to appear more charismatic and persuasive then he or she can use body language to send a message. As an example, try Googling "Body language postures and testosterone". It sounds silly at first but it's crazy.