i just finished 'the definitive book of body language' and i think its one of the most compact and useful body language books out there. it has basically every body language interpretation.
Leil Lowndes has a book called '
Undercover Sex Signals' and thats good for figuring out female body language and is basically about IOI's. its written at like a grade 6 reading level which is kind of annoying but the pictures are good to uncover and now that i think about it, has helped me out more than i thought it would have.