Abstract: The use of criminal informants in the U.S. justice system has become a flourishing socio-legal institution. Every year, tens of thousands of criminal suspects, many of them drug offenders concentrated in inner-city neighborhoods, informally negotiate away liability in exchange for promised cooperation, while law enforcement at the local, state and federal levels rely on ever greater numbers of criminal actors in making basic decisions about investigations and prosecutions. While this marriage of convenience is fraught with peril, it is nearly devoid of judicial or public scrutiny as to the propriety, fairness, or utility of the deals being struck. At the same time, it is a quintessential expression of some of the most contentious characteristics of the modern criminal system: law enforcement discretion, secrecy, and the increasing informality of the adjudication process. The informant institution is also an under-appreciated social force in low-income, high-crime, urban communities in which a high percentage of residents - as many as fifty percent of African American males in some cities - are in contact with the criminal justice system and therefore potentially under pressure to snitch. By relying heavily on snitching, particularly in drug-related cases, law enforcement officials create large numbers of informants who remain at large in the community, engaging in criminal activities while under pressure to provide information about others. These snitches are a communal liability: they increase crime and threaten social organization, interpersonal relationships, and socio-legal norms in their home communities, even as they are tolerated or under-punished by law enforcement because they are useful. This Article conceptualizes the informant institution as an engine of the modern criminal system, both in its operation and its expressive value. Informing shapes the practice of plea bargaining, it heavily influences prosecutorial discretion, and is a major symptom of the increasingly administrative, non-public, non-adversarial nature of the U.S. justice system. For all these reasons, the informant institution has a potentially significant normative impact on systemic legal values; the expressive value of the widespread practice of rewarding criminals even as they continue to commit crimes warrants careful scrutiny. The Article also hypothesizes the harms imposed by the informant institution on socially disadvantaged, high-crime communities in which snitching is common. These harms may include increased crime, the erosion of trust in interpersonal, familial and community relationships and other psychological damage created by pervasive informing, the communal loss of faith in the state, and the undermining of law-abiding norms flowing from law enforcement's rewarding of and complicity in snitch wrongdoing. Because what ails the informant institution is centrally a function of the increasingly secretive discretionary exercise of criminal law enforcement authority, the Article proposes reforms primarily of the sunshine variety. The reforms aim to reduce the secretiveness and lack of accountability surrounding the informal adjudication of informant liability, and to increase legislative control over and public awareness of this quintessentially secretive executive practice.