This volume contains revised and extended versions of the papers presented at the Second International Workshop on Non-Monotonic Reasoning, held in Grassau (FRG), June 13-15, 1988. The workshop brought together researchers with different backgrounds, including non-monotonic logic, logic programming, truth maintenance and philosophy. Their papers contain substantial advances to the logical foundations of non-monotonic reasoning, its computational realization, and its application to the formalization of common sense reasoning. The book presents a snapshot of the state of the art in this research area, and provides in-depth discussions of current problems and approaches.