Contemporary drug therapy fails to control epileptic seizures in some 30% of patients, resulting in the need to employ other measures when they appear practicable. A good deal of potentially relevant statistical detail is available regarding the outcomes of the available antiepileptic therapies, but its interpretation is sometimes difficult because of uncertainty about the types of epilepsy to which it applies, and because of deficiencies in knowledge of the natural histories of the various epileptic syndromes, if untreated. The actual shortcomings in the contemporary treatment of epilepsy appear to arise not only from the limited curative capacities of the available therapies, but from a number of deficiencies in knowledge concerning the significant aspects of what should determine treatment policy and the optimal employment of antiepileptic drugs.