A panel of senior clinicians critically reviews the many forms of status epilepticus (SE), their causes, manifestations, methods of diagnosis, and appropriate treatments. The emphasis is on the disease as encountered by the clinician in the field and the importance of correct recognition and diagnosis. The authors provide for each form of SE the underlying genetic, biological, and developmental background, the pathophysiological processes, as well as the precipitating factors that lead to an episode. For the difficult problem of diagnosing nonconvulsive SE, they offer detailed syndrome classifications, differential diagnoses, descriptions of seizure “imitators,” notes on unusual behavioral and cognitive manifestations, and carefully delineated clinical presentations. Additional highlights include striking EEG reproductions that provide classic examples of patients in SE, SE in very young children and neonates, and an analysis of the cellular physiology and processes occurring during SE.