Any protege of the late James Beard deserves more than a touch of notice--which, judging from Fobel's previous five cookbooks and at least one award, has already been accrued. Number six is sure to join the stable of library favorites, centering as it does on pure and simple casseroles. Some of the 100 or so dishes are familiar comfort foods with a few changes, such as chicken potpie with a bacon crust. Others represent more unusual variations on a theme, such as a potato-cheddar kugel without noodles or raisins. Accompanying text imparts information about pan equivalents and instructions for freezing; typical of the author's treatment is his debate about appropriate ingredients for a tuna casserole. Canned or fresh tuna? Cream-of-mushroom soup or a substitute? (The issue is easily solved by the creation of two recipes.) - Barbara Jacobs; 192p-