Papers in this collection include: Alan Borning, Bjorn N. Freeman-Benson, and Molly Wilson, "Constraint hierarchies", Lisp and Symbolic Computation 5:223-270, 1992. Philippe Codognet and Vijay Saraswat, "Abduction in Concurrent Constraint Programming", March 1992. Vijay A. Saraswat, Johan de Kleer, and Brian C. Williams, "ATMS-based constraint programming", Xerox PARC, October 24, 1991. Joxan Jaffar, Spiro Michaylov, Peter J. Stuckey, and Roland H.C. Yap, "An Abstract Machine for CLP(R)", November 1991. Thierry Le Provost and Mark Wallace, "Generalised Constraint Propagation Over the CLP Scheme" ECRC Technical Report ECRC-92-1, February 1993. Also appears in the Journal of Logic Programming, 1993. Vijay A. Saraswat, Martin Rinard, and Prakash Panangaden, "Semantic foundations of concurrent constraint programming", October 1990. Also appears in POPL-91. Bjorn N. Freeman-Benson and Alan Borning, "Integrating Constraints with an Object-Oriented Language", Proceedings of the 1992 European Conference on Object-Oriented Programming, pages 268-286, 1992. Vijay A. Saraswat, "Concurrency in the Lambda-calculus: Higher-order Concurrent Constraint Programming", Xerox PARC, December 4, 1991. Prakash Panageden, Vijay Saraswat, P.J. Scott, and R.A.G. Seely, "What is a Constraint System?", December 8, 1991. Some of these papers come from the "Constraint Programming Paper Archive" located at Aarhus University, Denmark, and accessible by anonymous ftp as ftp.daimi.aau.dk:pub/CLP/. For further information on the archive, contact Brian H. Mayoh .