Somewhere amid all the prattle from tenured sociology professor sorts and journalists about wide social trends are investors who, with a keen eye, can make a buck from identifying the few social trends that are a.) real and b.) bankable. The most sizeable challenge to this method of investing is that so many who claim trends are daffy. And to go out in search of substantive trends, you need to read widely and wade through many trend stories -- the worst, most unreliable reports you'll see in journalism. (Before wading, put on your hip-highs. This is an area where anecdotes and hunches based on narrow personal experience rule.) That is why no book is more essential as a rough reference for investors in social trends than Microtrends: The Small Forces Behind Tomorrow's Big Changes. The book, which gets the Business Press Maven "Help" label, should be thought of as a clearinghouse for trend ideas. It is written by Mark J. Penn, the CEO of Burson-Marsteller and the Clinton pollster widely credit with tapping into the "soccer mom" phenomenon. Flip through the book and see where you get ideas. Even if you don't, you'll be entertained, as in the section on how uptown souls are getting tattoos in remarkably high numbers. Penn traffics in the old rumor (neither confirmed nor denied) that former Secretary of State George Shultz has a Princeton tiger tattooed on his backside. He also speculates that tattoos are here to stay and will evolve into 3-D and disappearing forms.