In this paper we describe an implementation of actors in Smalltalk-80,
named Actalk.
Actors are active and autonomous objects,
as opposed to standard passive Smalltalk-80 objects.
This attempt is designed as a minimal extension
preserving the Smalltalk-80 language.

An actor is basically a serializer built around some usual Smalltalk-80 object.
We will study the cohabitation
and synergy between the two models of computation:
transfer of a single thread of activity
between passive objects with a call/return discipline,
and simultaneous activities of autonomous actors communicating through
asynchronous communications.
We propose a sketch of methodology in order to have a safe
combination between these two programming clich\'es.
As an example we propose a slight change into the MVC (Model View Controller)
model for interface design in order to integrate it with the actors.

We show how to extend the Actalk kernel into various extensions
to define the basic Actor model of computation,
higher level programming constructs such as the 3 types of message passing
(asynchronous, synchronous, and eager)
proposed in the ABCL/1 programming language,
and some distributed architecture.
All these examples are constructed as simple extensions of our kernel model.