What is the role of the olive in cerebellar operations? And what is the role of the cerebellum in the sensory and motor functioning of the nervous system? It is clear that the olivo-cerebellar network plays a key role in the managing of vertebrate motor control, as lesions in this network cause motor deficits in humans and animals. However, it is increasingly becoming clear that the olivo-cerebellar system is involved in the control of more than simple motor behaviors. The elegant and almost geometric organization of the olivocerebellar network lends itself to performing these complex operations. In this review, the salient anatomical, physiological, and clinical features of this system are discussed. A computer-assisted visualization system is used to illustrate some of the anatomical points. The idea that the cerebellum and the olivo-cerebellar networks are perhaps in the upper echelons of the hierarchy of brain functioning, if such a hierarchy indeed exists, is discussed. NEUROSCIENTIST 13(6):616—625, 2007. DOI: 10.1177/1073858407299286