A mixture of case study and personal portrait, this documentary report has a seventeen year old Chilean murderer as its subject, the Valparaiso slums and prison as the setting and the seemingly motiveless murder as its point of departure. During the seven months the author spent is getting acquainted with Manuel, the boy's cold poise and Teddy Boy nonchalance never faltered. Handsome, vain and verbal, he told his story eagerly and only at the end did he face reality and come to regard himself as a criminal, at least in the judgment of the world. In order to present as full a picture as possible, Manuel's enigmatic character is described as he appeared to the courts and the press, to his fellow prisoners, and to the author himself. It is the last section that probably contributes most to an understanding of the boy. There can be no pat answer as to what creates a juvenile criminal, but the social environment of slum life, the need for personal attention, and the strictly practical struggle for wherewithal all play their familiar roles. Why Manuel murdered a homosexual lawyer without promise of material or any other gain could well lie buried in the mystery of habit--habitual thevery, male prostitution, and an intimate acquaintance with violence. Although the book makes no pretense of sociological analysis, it is almost a paradigm case which will most likely be of interest to those in the field. Its value also lies in the author's personal concern for the individual.