This chapter presents an overview and practical approach to conceptualize manifestations of cerebellar lesions and outlines the principles that govern the cerebellar contribution to cognition and emotion as well as to sensorimotor function. Lesions of the cerebellum have been regarded as producing motor impairments. The cerebellar motor syndrome is characterized by wide-based and unsteady, or ataxic, gait; incoordination, or dysmetria, of the arms and legs; articulation impairment, or dysarthria; and eye movement abnormalities that disturb vision. The cerebellar cognitive affective syndrome (CCAS) results from lesions of the posterior lobe, characterized by clinically relevant deficits in executive function, visual spatial performance, linguistic processing, and dysregulation of affect. The connections of the cerebellum with brain circuits are implicated in psychiatric illness. Applying repetitive transcranial magnetic stimulation (TMS) to the limbic cerebellum in the vermis improves psychiatric disorders such as schizophrenia by upregulating cerebellar modulation of cerebrocerebellar circuits engaged in cognition and emotion.