This volume presents the experience of the Zurich Epilepsy Surgery Center with stereotactic recordings and stimulations of various subcortical nuclei, with special reference to the Forel H fields, the thalamic nuclei and the periaqueductal gray matter. Stereotactic lesions structures have frequently been performed with the aim to prevent seizure spread along preexisting and preferred seizure propagating pathways or to directly destroy diseased areas of the brain that act as a focus of epileptic discharges. Although the usefulness of stereotactic epilepsy surgery has been repeatedly challenged, the extensive knowledge deriving from early attempts to suppress seizures by stereotactic epilepsy surgery is relevant to the renewed interest in neurostimulation for the treatment of epilepsy. Deep Brain Stimulation (DBS) of these structures aims to influence these key "pacemaker" areas in the brain and is gaining increasing interest as a possible new surgical modality for treatment of patients with intractable epilepsy. Thus, the aim of this volume is to improve understanding of the involvement of subcortical structures in seizure genesis and propagation, and to address the important issues of DC recording/polarisation and biochemical measurement of excitatory and inhibitory transmitters released in the primary epileptogenic area during epileptic discharges.