The importance of the cerebellum in relation to movement control has long been established, but in recent years, the question has been raised as to whether the cerebellum may also have a role in cognition or thought processes. In this chapter, this question, which has been at once intriguing and controversial (Barinaga 1996), will be considered, especially in view of the uniformity of cerebellar anatomy. From this uniformity, it would follow that the same basic type of computation that is performed in the vestibulocerebellum and the spinocerebellum would also be carried out in the neocerebellum (lateral cerebellum, cerebellar hemispheres). Assuming that the neocerebellum does participate in cognitive phenomena or is essential for such mental activities, interfacing the cerebellum with the cerebrum (cerebral cortex), and the specific nature of their joint transactions, is formidable. It is far beyond the reach of this text to venture solutions to these questions. Rather, this chapter summarizes some of the history and findings in relation to the question of the cerebellum and cognition. If signal adaptive control is indeed an appropriate model for the vestibulocerebellum and the spinocerebellum, and for the evidently motor functions of the cerebrocerebellum, then because cerebellar anatomy is essentially uniform throughout the “cognitive cerebellum,” there would seem to be a high probability that those parts of the lateral cerebellum that appear to be involved with cognition are also functioning as adaptive controllers.