NONFICTION : WHAT THEY KNOW ABOUT YOU <i> by Bernard Asbell and Karen Wynn (Random House: $20; 302 pp.).</i>

This is the equivalent of a body-building course for a 90-pound weakling. Find yourself getting conversational sand kicked in your face at dinner parties? Read this compendium of information and learn a little bit about everything. Guaranteed to get you past the hors d’oeuvres before you run out of material--and then you always can change subjects. The authors have done what none of us has the time or stamina to do: They’ve read through thousands of research studies and come up with the best tidbits, arranged by category, from “Your Outer Self and What It Says About You” to “Crime, Violence and Aggression.” Some of the information is rather inconsequential--a professionally diagnosed neurotic is likelier to read and believe his horoscope than someone who isn’t neurotic--but some of it is daunting. That same neurotic, according to another study, is smarter, better educated, likelier to have a job, and earns 23% more than his psychologically healthy counterpart.