An instructive and entertaining book for those public and private investigators who are potential undercover agents, this book approaches the topic from three angles: how to handle informants, how to investigate suspects, and how to be an undercover agent. Undercover places emphasis on the law enforcement agent but does not overlook the private investigator who may be assigned to work in an undercover role in business or industry. The first edition of this book quickly became the classic text for a whole generation of law enforcement personnel, and the name Carmine Motto, now retired from the secret service, is known throughout the country. Both authors contribute years of personal experience and use actual case anecdotes to focus attention on the triangle of interpersonal relationships among the informant, the suspect and the investigative agent. The motivations of the informant are detailed and analyzed to determine his reasoning and willingness to assist the investigator; the suspect is examined relative to his background, associates and capabilities; and, the investigative agent is instructed in protecting the identities of and handling of informants while gaining the confidence of the suspect. This edition of Undercover modernizes the writing, replaces the photographs, and updates the cases to provide insight into the highly intriguing and fascinating human intelligence and evidence gathering method that has captured the public's attention through movies, television and newspapers.