Answer set programming (ASP) is a form of declarative programming oriented towards difficult (primarily NP-hard) search problems. It is based on the stable model (answer set) semantics of logic programming. In ASP, search problems are reduced to computing stable models, and answer set solvers -- programs for generating stable models -- are used to perform search. We are interested in the theory of stable models, in the methodology of answer set programming, and in the design of answer set solvers.