A new definition of strategic stability is shown to satisfy all of the requirements given by Elon Kohlberg and Jean-Francois Mertens (1986). The definition follows the general form of the original definition of Kohlberg and Mertens, but, rather than working with perturbations of the payoffs or strategy space, works directly with perturbations to the best reply correspondence. With the appropriate topology on this space of perturbations, the resulting definition does satisfy all of the requirements given by Kohlberg and Mertens. It is shown that one does not have much freedom in the topology one uses.