Of course: ""A party is an act of faith on the part of the host."" So who better to celebrate its blessings than the frocked author of Supper of the Lamb and Food for Thought? But the thing must be done advisedly, and ""by orderly and necessary stages."" So the cocktail bash (""a slow leak"") won't do. Father Capon would rather we faced 50 drop-ins unprepared and unflustered, set out all the potables on hand--and put up a pot of pasta for a leisurely, convivial repast. His forte, indeed, is the impromptu occasion on which all hands are pressed into service (""Morton at the meat grinder, Doreen ready to dice, Betty at the bowl and Willy with the Wonder Bread""); and he supplies a benison of recipes to turn refrigerator tag-ends into a culinary tour de force--all the more certain to establish the host as ""one who understands the difference between cooking for people and following recipes to set before them."" Some of the same sang-froid is called for on more formal occasions, however, since Capon is cavalier about quantities throughout. But he is firm about precepts. A sit-down dinner is best dressed up to; appetizers ""must be out when the guests arrive"" and the host must be in evidence (hence cold hors d'oeuvres and cook-ahead main dishes); soups merit attention--but they must be exceptional soups (""a clear and powerful broth"" qualifies); and desserts should not be dietary obeisances--""For if there is ever a time when the Jerusalem of Faith most dependably discloses itself as the Heavenly City in fact, it is over dessert, coffee and liqueurs."" Hospitality has seldom had a more benign aspect.