Ready to fall like a ripe avocado into the eager arms of graduates of The New York Times Cookbook (over 100,000 copies sold), this variant includes over 400 menus along with the over 1,000 recipes never before revealed in book form. Expect the former exhilarating standards -- exciting foods developed with the same serene institutional benevolence the Times seems to bring to all its associated endeavors. The Times cookbook alumnae will know all the pitfalls, which are minor ones --and a few minutes to vegetable-cooking time (vegetable qualities vary from locale to locale); prepare to do some gourmet shopping. However, for the party giver, or the mildly experimental cook, no cookbook has proved quite so satisfying for interest, variety and reliability. The menus are manna for the anxious, uninspired hostess, and of course there are the photos pointing the way.