This is one of those amiable, well-intentioned and not terribly illuminating books in which people -- young, middle-aged and aging, hetero, homo, married, shacked up, divorced and widowed -- talk informally to an openminded, uncensorious interviewer about their lifestyles, sexual partners, marital hopes, children, affairs, hang-ups and dead-end relationships without sounding either confessional or apologetic. In this case the person lending the sympathetic ear is Megan Terry, author of the award-winning play Viet Rock and herself a liberated believer in new ""experiments in living."" Curious then, that so many of the men and women who unburden themselves to her should be so unabashedly clinging to tradition -- like the 53 year-old teamster who thinks that TV and the pill have ruined marriage or the Connecticut matron who states quite firmly that in order to achieve a happy union a woman must give up ""a mind of her own"" and ""let him think he's boss."" Not all are that square of course and some, like the ex-nun schoolteacher now living in a commune (""I love Jesus, I call him Sam when I talk to him""), have certainly strayed a long way from the precepts of their parents. What it all proves -- apart from affirming the let-a-thousand-flowers-bloom view of interpersonal relations -- we're not quite sure, but since Ms. Terry has interviewed such a mixed bag of just plain folks, any reader should be able to find at least one soul mate.