The SIRC Guide to flirting is a wonderfully tongue in cheek but learned compendium of info about flirting:

... in some rather Puritanical cultures, such as Britain and North America, flirting has acquired a bad name. Some of us have become so worried about causing offence or sending the wrong signals that we are in danger of losing our natural talent for playful, harmless flirtation.

So, to save the human race from extinction, and preserve the foundations of civilisation, Martini commissioned Kate Fox at the Social Issues Research Centre to review and analyse all the scientific research material on interaction between the sexes, and produce a definitive guide to the art and etiquette of enjoyable flirting.

Psychologists and social scientists have spent many years studying every detail of social intercourse between men and women. Until now, their fascinating findings have been buried in obscure academic journals and heavy tomes full of jargon and footnotes. This Guide is the first to reveal this important information to a popular audience, providing expert advice on where to flirt, who to flirt with and how to do it.

[pointer from Dave Evans at Online Dating Insider]