Parents should continuously read books that may help them in their parenting skills,"" declare the optimistic authors of this latest--and exhaustive--manual for would-be effective heads of families. To help, in their 15th and final chapter, entitled ""Parentship Resources,"" they list 32 more titles (including their own 1983 book, Parent Burnout) for parental scan. With so much in print already, and so many burned-out parents, what's new? Good communication with the children, fair discipline, thoughtful motivation, careful planning, sharing of family responsibilities, thorough parental self-examination--a thrice told tale. . . and more. But there is a new wrinkle in P.L.U.S. Parenting (""P.L.U.S."" is ""Parent Leadership Using a System""), and it may mm a few heads: Parents are (or should be) the leaders of their families, and they need the same leadership and management skills the executives of any organization require. If the business of America is still business, at last the way may have been found to get fathers interested in functioning like fathers, and mothers back to mothering: make them executive vice-presidents. Gimmicky? Sure, but its familiar prescriptions for family health are still sound. Many chapters include a self-administered test or two--on ""parentship"" style, children's ""followership,"" family climate, listening skills, decision-making abilities, etc. Principles of financial management are outlined, methods of gathering information are detailed, Almost every conceivable transaction between parent and child is broken down into steps that any middle manager can and should follow. Despite its artless style and excessive length, this self-helper is sincere and responsible. It may reach some of those parents who are put off by a psychological approach. If the book sounds chilly, it really isn't. It's a good thing, just too much of one.