This paper offers an overview of some important issues concerning the robustness of chaos in dynamical systems and their applications to the real world. PACS numbers 05.45.-a, 05.45.GgChaotic dynamical systems display two kinds of chaotic attractors: One type has fragile chaos (the attractors disappear with perturbations of a parameter or coexist with other attractors), and the other type has robust chaos, defined by the absence of periodic windows and coexisting attractors in some neighborhood of the parameter space. The existence of these windows in some chaotic regions means that small changes of the parameters would destroy the chaos, implying the fragility of this type of chaos.Contrary to this situation, there are many practical applications, such as in communication and spreading the spectrum of switch-mode power supplies to avoid electromagnetic interference [15, 16], where it is necessary to obtain reliable operation in the chaotic mode, and