Irish actor Gabriel Byrne was browsing in a little bookstore in Halifax, Nova Scotia, recently while on location making a movie, when the owner recommended a first novel by Regina McBride called The Nature of Water and Air, published as a Scribner paperback original in May. He was so impressed with the book that he sought out the author, a writing teacher at Hunter College in New York, to ask if the movie rights had been sold. They hadn't, so he promptly snapped them up from Jody Hotchkiss at Sterling Lord, working on behalf of McBride's literary agent, Regula Noetzli, and has already begun co-writing a screenplay with the author; he plans to direct, produce and, possibly, star in a movie version. The tale, set on the west coast of Ireland, is an erotic love story revolving around a mother and daughter, and the book was originally bought by editor Doris Cooper at Morrow. She took it with her when she moved to Simon & Schuster, where it has 30,000 copies in print and is a choice of B&N, Borders and Book Sense.