An outline of the relevant provisions of the West German Basic Law (Constitution) focuses on the right of privacy, the secrecy of telecommunications, and the inviolability of the home. The article then discusses the statutory authorization of telephone surveillance and audio-surveillance by private parties. This is followed by an analysis of the legal consequences of illicit wiretapping, the uses to which legally acquired information can be put, and how the fruits of audio-surveillance can be introduced into evidence at trial. Overall, tape recordings made by or upon request of state agencies without proper authorization are not admissible as criminal evidence. Illegal tape recordings by private individuals are admissible if their importance to justice outweighs the violation of the defendant's rights. Evidence derived from illegal wiretaps is admissible if the wiretap was conducted in the course of a criminal investigation; derivative evidence is inadmissible if the illegal wiretap was conducted in the interest of State security. 160 footnotes.