Lindsay, R.K., B.G. Buchanan, E.A. Feigenbaum and J. Lederberg, DENDRAL: a case study of the first expert system for scientific hypothesis formation, Artificial Intelligence 61 (1993) 209-261. The DENDRAL Project was one of the first large-scale programs to embody the strategy of using detailed, task-specific knowledge about a problem domain as a source of heuristics, and to seek generality through automating the acquisition of such knowledge. This paper summarizes the major conceptual contributions and accomplishments of that project. It is an attempt to distill from this research the lessons that are of importance to artificial intelligence research and to provide a record of the final status of two decades of work. Correspondence to: R.K. Lindsay, University of Michigan, 205 Zina Pitcher Place, Ann Arbor, MI 48109, USA. Telephone: (313) 764-4227. Fax: (313) 747-4130. E-mail: firstname.lastname@example.org. * This research was supported by the National Aeronautics and Space Administrations, the Advanced Research Projects Agency of the Department of Defense, and the National Institutes of Health. This paper draws upon , expanding and updating that account in light of subsequent developments and the benefit of hindsight. Large portions of descriptive material are taken nearly verbatim to make the present paper self-contained since the book itself is no longer in print. 0004-3702/93/$06.00 © 1 9 9 3 Elsevier Science Publishers B.V. All rights reserved 210 R.K. Lindsay et al.