Books: Sensational

In the middle of the world's biggest war, a shrinkingly sensitive first novel with a 1920 theme has become a 1943 bestseller.

The novel: Equinox (Allan Seager; Simon & Schuster; $2.75). The theme: platonic psychological incest.

Equinox tells the story of Widower Richard Miles, a foreign correspondent who returns to the U.S. to take care of his daughter, Mary, 17. Richard's aging ex-mistress declares that the girl's love for her father and his for her are not innocent. The machinations of an amateur psychiatrist convince Richard and Mary that their love is incestuous....