You can get out of your party clothes now and just enjoy the homemade goodness of a plate of cookies. Nancy Baggett, revered baking teacher and long-time cookie connoisseur, has collected recipes from all over our cookie-loving country to create The All-American Cookie Book. She includes little-known regional gems, rediscovered heirlooms, favorites from both small-town sweet shops and chic urban cookie boutiques and some of her own inventions. They're here in all shapes and sizes, from monster to miniature, rolled, dropped, piped, filled with fruit, nuts and candy, iced, spiced, topped with streusel and meringue, brownies, chews, chunkies, jumbles, sables, sandwiches, wafers, meltaways and macaroons. And by incorporating personal reminiscences, culinary history, observations of the current cookie scene and colorful lore into the introductions for this full-range of recipes, Nancy gives us the story-behind-the-cookie and the story of a good, old American baking tradition. That's how the cookie crumbles from simple Nineteenth-Century Sugar Cookies to complete plans for a Gingerbread House with all the trimmingsSybil Pratt has been cooking up this column for more than five years.