Qualitative Reasoning about Physical Systems: An Introduction (D.G. Bobrow). A Qualitative Physics Based on Confluences (J. De Kleer and J.S. Brown). Qualitative Process Theory (K.D. Forbus). Commonsense Reasoning About Causality: Deriving Behavior from Structure (B. Kuipers). How Circuits Work (J. De Kleer). Qualitative Analysis of MOS Circuits (B.C. Williams). Diagnostic Reasoning Based on Structure and Behavior (R. Davis). The Use of Design Descriptions in Automated Diagnosis (M.R. Genesereth). VERIFY: A Program for Proving Correctness of Digital Hardware Designs (H.G. Barrow).