Concept of MAS born in late 40s as computational devices ( agents ) with some properities which cooperated parallel. First "agent" machine was Von Neumann machine which has capability to reproduction. With Neumann friend Stanislaw Ulaman they create idea of cellular automata.
Next step in agents history was Game of life proposed by John Conway with it's simple checker roules. First concept of agent based model was invited by Craig Reynolds. He observed biological agents for obtaining the rules for virtual world. First development of MAS was wrote by Joshua M. Epstein and Robert Axtell. The Sugarspace had capability to simulate such behavioures as seasonal migrations, pollution, sexual reproduction, combat, and transmission of disease and even culture.
The most exciting think in MAS is it's simplicity from each particular agent point and this that they can create toghether the complex enviroment and solve nontrivial tasks. Capability to simulate very different beavioures make them simillar to life creatures. The most popular models for MAS are insects. Ants are good examples. About agents we can say a few thinks: