Each book Marian Tracy publishes is promptly seized upon by those who claim to know what constitutes a properly equipped kitchen bookshelf. Many find that her books come off the shelf for practical use perhaps more often than any other specialty cookbooks. This is one assuredly will be added, although it comes close to being a more general cookbook than - for instance- the casserole cookbooks. Here are party dishes and home dinner dishes, one dish meals, hearty main course dishes with suggested accompaniments, aspics and leftovers. The significant point to make, however, is that these are unusual ways of preparing the basic roasts, poultry, variety meats, seafood, cheese, eggs, pasta and vegetables, a welcome spur for the jaded housewife.