The undercover police work addressed in this study encompasses those operations where police personnel deceptively infiltrate criminal operations to observe and in some measure participate in criminal activity. In determining international norms for the right of privacy, the author reviews decisions of the European Court of Human Rights, notably the Huvig and Kruslin case and the Ludi case. The Court held in Ludi that the use of police infiltration was not a violation of Article 8 of the Schengen Convention concerning the right to privacy, and thus it was not necessary to address the issue of the quality of the norm on which the policing technique was based. The Court argued that the applicant "must have been aware that he ran the risk of encountering an undercover police officer whose task would be to expose him." The Court apparently holds that the scope of the right to privacy varies depending on whether one is involved in criminal activities or not. In Kruslin and Huvig, however, the Court ruled that telephone tapping was a violation of Article 8 and was as such "an interference by a public authority" with the exercise of the right of privacy. Thus, according to the Court, any police use of telephone tapping should be governed by clear and precise laws on when and how police may intercept telephone conversations. A review of laws that govern undercover policing in the five countries examined shows no consensus on the necessity of having detailed legislation on the issue; neither is there agreement on whether undercover policing should apply to a wide range of criminal offenses or to a limited number. Only one of the countries studied, Germany, provides for the formal obligation of notifying a person afterwards of the fact that he/she has been put under the surveillance of an undercover agent. The author argues for the adoption of detailed legislation on all special policing techniques that involve exceptions to the right to privacy. 81 footnotes