BookReviews

Gul A. Agha's Actors: A Model of Concurrent Computation in Distributed Systems (The MIT Press, Cambridge, Mass., 1987, 144 pages, $25.00, ISBN O-262 010925) is part of the MIT Press Series in Artificial Intelligence. This volume is edited by Patrick Winston, Michael Brady, and Daniel Bobrow. In the actor formalism, pioneered by Carl Hewitt (1977), one perceives abstract computational agents, called actors, that are distributed in space. Each actor has a mailbox (and a mail address) and associated with each actor is a behavior. One actor can influence the actions of another actor only by sending it a communication.