Bland thriller, with some comic teen-age dialogue, revolving around the exercise fad. At a Chicago hot-dog stand in 1975, Maureen Dietz, tending her two children in the car, sees a pair of thugs (who had followed her about in a supermarket earlier in the day) attack and kill her hot-dog-bearing husband, David, with a baseball bat, then smash her window attempting to get at her. As the psychopathic thugs, Cal and Marty, drive away, Marty says, ""The one in the car with the kids. She remembered us. . .We should have dragged her in the truck this morning and stuck it to her after we saw her at the damned A and P. We owe her, Cal. We owe her.""Eight years later, Maureen has pulled herself out of depression by opening a fitness center and devoting herself to exercise and her mystical philosophy of the Now in exercise. Is Maureen repressing the past in her exercise regimen? Her two kids, Nancy, known as Princess Daisy, and Miles, who is into bodybuilding although his frame is not old enough for it, seem to have survived the horror of their father's murder. But when policewoman Helen Katz gives her the file on the murder, and tells her that a new-dead cop may have identified the murderers, Maureen gives a TV interview that is picked up nationally, and soon Marty and Cal, hiding out in California, decide to return to Chicago and get rid of her. Other witnesses from the hot-dog stand murder soon are dropping like flies, their heads battered, and Maureen is obviously the next victim. The climax in a dark gym is foreseeably active, but the novel's final twist carries a sad weight. Exercise in Terror may be about running the track and exercising to Bach, but overall it's simply pedestrian, especially the banal characterizations of the two psychopaths.