Every Spring and Fall, in the woods of the Black Forest, mathematicians from West-Germany and other countries gather at Oberwolfach for the “Arbeitsgemeinschaft Geyer-Harder” to teach themselves in a joint effort new theories or results. At each meeting the topic and organizers of the following Arbeitsgemeinschaft are chosen after an evening of discussions by democratic vote. The organizers then prepare a detailed program for the conference which is posted in the mathematical institutes. Everyone interested in taking part in the meeting has to volunteer for one of the talks in the program. The organizers then choose the actual speakers. The Arbeitsgemeinschaft of April 1986 was devoted to the work of Beilinson and Bloch on regulators. The meeting centered around Beilinson’s article “Higher regulators and values of L-functions”. It was generally felt at the conference that the joint effort made to understand this fundamental paper should not be lost, and should be helpful to others. Hence this volume. Most of its chapters are based on talks at the meeting; others have been added in order to give a coherent account of the conjectures and some of the known evidence for them. In the name of all participants we want to express our gratitude to the Mathematisches Forschungsinstitut Oberwolfach, which makes the Arbeitsgemeinschaft possible.