Miss Dillon writes about characters locked into the patterns of ""mature adaptation"" -- about the subtle push and tug of habit and disappointment and the way a single routine can work equally and simultaneously for survival and self-destruction. In ""Second Bedroom"" a mistress's acceptance of her unlovable lover becomes the cause for his rejection of her; in ""Baby Perpetua"" a woman writer's desperate wish for easy passion prevents love and passion from coming easily or at all. Evidently most of these, and the best, are written for a female audience and from female experience; but others with male protagonists (""The Newsboy,"" ""Rape,"" ""The Uncertain Hours of Willie Post People"") pursue the same theme at greater distance, with imaginative skill if less conviction. These latter aren't likely to broaden the audience appreciably, and not all women will like the way the author worries the last nuance from moments of uncertainty and psychological stalemate. For readers who can recognize the truthful detail and yet not be unstrung by it -- the post-analytic elite.