Some of these issues focus on how targets should be selected for deceptive investigations, how the innocent should be safeguarded, how informants should be screened and monitored, the effect of the fifth amendment's injunction against self-incrimination, and how to rationalize the invasion of privacy needed in crime control. Although the use of informants and undercover agents has long been recognized as vital to successful law enforcement, their use has recently become the subject of systematic public scrutiny. Expert opinion is deeply divided about the necessity for ABSCAM-type investigations and the particulars of such operations. Seven essays focus on the nature of the criminal conduct involved in the ABSCAM investigation, methods by which it can be detected, and risks of such operations to democratic values. Specifically, the essays examine ABSCAM as a fair and effective method for fighting corruption, invisible offenses as a challenge to minimally intrusive law enforcement, hidden costs of undercover operations, issues in police undercover work, the licensing of criminals via police and informants, fairness and target selection in deceptive investigations, and an administrative perspective of undercover investigations. References and notes