Introduce, straight off, a large and varied cast with more interrelationships than first appears. . . . Make your murder victim a heel that any number of the others have good reason to kill. . . . Put the investigating heroine in apparent danger because of what she knows. . . . And make her suspect, a little later than readers will, the obvious culprit--who, of course, didn't really do it at all. St. John practices her own rules as her student heroine libby learns them at a tacky little writers' conference on an Alabama campus, libby plays a dual role of detective and author as she bases her assigned mystery novel on the real murder (or murders, as the conference gets going). It's all executed neatly enough to engage other would-be practitioners--or at least those who aren't put off by the corny collegiate incidentals.