Following an overview of the general characteristics of an effective undercover agent, the importance of law enforcement and human relations experience as well as advanced education is emphasized. The discussion of the selection procedure notes the importance of supervisors being thoroughly familiar with undercover candidates' personalities, occupation commitment, character, and performance. Testing includes the traditional screening devices as well as psychological testing and a test of retention powers. The family life of the candidate is given special attention, since undercover work puts great strain in marital and family relationships. It is recommended that undercover agents be single. The section on interviewing advises that interviews by undercover supervisors focus on attitudes and personality characteristics relevant to the particular undercover work to be done. The description of the undercover training done by the New York City Police Department depicts the training methods for undercover narcotics agents, which includes role playing, the imputation of knowledge about drugs, and on-the-street training. The discussion of setting up a cover considers the construction of a cover story for the agent, the selection of a transportation vehicle for the agent, the agent's undercover living quarters, and communications between headquarters and the agent. The means whereby an agent can terminate an assignment without alerting the subjects of the investigation are examined in the concluding section as well as some possible unintended consequences of undercover activity.