Crossing arms has never been the same since I read Persuasion (James Borg, 2007, Pearson Education). I strongly recommend the book for its great insights into body language, memory control and conversational dexterity.
This great infographic is another reminder of how important both mastering and interpreting non-verbal communication is and also how many times we come across people in meetings who get it so wrong. Showing some renewed interest in the topic, I also dug up this recent and fascinating BBC documentary on persuasion – remember S.P.I.C.E.!