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This work is devoted to the study of Dynamical Systems defined by Autonomous Retarded Functional Differential Equations. In general, we don't have backward continuation of solutions then, we must work with Semy-Dynamical Systems. There is an extensive literature on Semy-Dynamical Systems but, usually, it is supposed that the phase space is of finite dimension or, at least, locally compact, wich it is not the case here, because we work with an infinite dimensional space. We try to present all the concepts of the cbassical theory of Dynamical Systems like, for instance, trajectories, invariant sets, critical and periodic points, limit sets , recursiveness, dispersiveness, attraction and stability of sets. We also prove a theorem about existence of periodic solution for equations in R² that lives S¹ invariant.