The book opens with a strange and frightening incident in the air from the perspective of a young American family on their way home to the United States.

Crichton is master of the thriller, and to pull in large numbers of contemporary readers and to successfully compete with other forms of entertainment, the thrills must begin immediately. It also helps greatly to have these events happen to sympathetic characters, to people with whom the reader can closely identify, to someone who is intriguing by the nature of his or her job or situation, or to vulnerable characters such as the young couple with a baby.

The technique of placing the sympathetic and interesting character in danger is continued in the person of the heroine, Casey Singleton. As a divorced mother of a seven-year-old, and as a woman who cannot rely on child support from her exhusband, Casey has...