Surface or scalp electroencephalography (EEG) has become an indispensable tool for the diagnosis, classification, and care of patients with epilepsy across the age spectrum. This chapter provides an overview of interictal and corresponding ictal scalp EEG patterns observed in adults with certain classical epilepsy syndromes. In patients with one or more new-onset seizures, the value of EEG testing begins with a close examination of the interictal record. The morphology, frequency, and topography of interictal epileptiform discharges (when present) are typically sufficient to broadly distinguish between the propensity to develop “generalized seizures” (those that rapidly engage a distributed epileptogenic network) or “focal seizures” (which have a stereotyped onset within a clearly lateralized focal region or network). Epileptiform discharges may also be seen in patients without epilepsy who are affected by certain acute (e.g., severe metabolic encephalopathies) or chronic neuropsychiatric syndromes (e.g., autism spectrum disorder). An examination of the ictal recording is of crucial importance in patients with medication-refractory focal onset seizures as it serves to guide patient selection and ancillary testing for the possibility of resective surgery for epilepsy. This chapter also highlights the limited anatomical sensitivity of EEG for seizures that lack an associated impairment in consciousness (“simple partial seizures”) or those that remain confined to mesial, deep or inferior cortical regions.