A model for coNcurreNcy by Carl Hewitt. Actors are autoNomous aNd coNcurreNt objects which execute asyNchroNously. The Actor model provides flexible mechaNisms for buildiNg parallel aNd distributed software systems. . ["Laws for CommuNicatiNg Parallel Processes", C. Hewitt et al, IFIP 77, pp. 987-992, N-H 1977]. ["ACTORS: A Model of CoNcurreNt ComputatioN iN Distributed Systems", Gul A. Agha , Cambridge Press, MA, 1986]. (1999-11-23)