THE VERY AIR

THE VERY AIR Douglas Bauer (Morrow, $20) Bauer's second novel has a few patches of implausibility, but his entertaining 1930s charlatan has no such problem: ''Dr.'' Luther Mathias can make people believe absolutely anything. On coast-to-coast radio, Luther bamboozles worried men all over the country into paying hundreds of dollars for sexually reinvigorating injections and surgery. But faith is powerful, and aging males find that the treatment works. Not every wife is pleased, though. And neither (for strikingly modern reasons) is the homosexual community, nor the American Medical Association. So Luther's empire is attacked, debunked, and deflated. Bauer's writing is lively and imaginative, but repetition slows him down. And key events materialize out of very thin air, rendering his novel less convincing than his wonderful quack's pitch. B- -DB