From the very beginning, Paul Steward, an editor, is thinking of killing his wife, his three children and himself at the end of the day. Program yourself for self-destruct and you may read it just to find out whether he has put himself out of his misery. If you remember, Mr. Horwitz' last book, The Married Lovers, was concerned with the same ruminations-recriminations--those of a psychiatrist versus his wife who attributed most of the wretchedness in the world to bad sex. Likewise, Paul has had very bad sex with Miriam--or none at all--even when it was indifferent ""like waiting for shredded wheat to soften."" Miriam isn't very happy either; in fact she's had a breakdown and now subsists on Valium. During this day Paul makes his final rounds at the office in the morning, goes to a brothel in the afternoon where he spends six hundred dollars with five girls who work him over for two hours (this is truly gross), and returns on the train which gets stuck in a tunnel giving him an opportunity to perform with his seatmate. Then he goes home to that loaded rifle. . . . Married Lovers, Natural Enemies, men and women, President Nixon and even James Reston--what a septic world it is, so full of hostility; it only takes Mr. Horwitz to make it seem even worse.