Almost anything written by Anita Desai is worth reading. This novel tells the stories of Uma and Arun, two Indian siblings, one living in India, the other in America. It's an eye-opening view into cultural differ-ences and the Indian experience at home and abroad. Desai is one of India's best-known novelists, author, too, of "Clear Light of Day," and "Baumgartner's Bombay."  (IDA172, $13.95)