Merely having the technical ability to perform functional neurosurgery is not sufficient. An understanding of key clinical concepts surrounding movement disorders lies at the heart of becoming a competent functional neurosurgeon in order to ensure correct patient selection and perioperative management. This chapter provides a thorough medical overview of the fundamental clinical aspects, including pathophysiology, diagnosis and medical therapy for the commonest movement disorders encountered in neurosurgical practice: Parkinson’s disease, essential tremor, and dystonia. A brief overview of the surgical management options and outcomes from surgery is discussed. Finally, some of the controversies related to the surgical aspects of movement disorders are examined.