The aim of this work is to present a clinical picture of Idiopathic Epilepsy, as a disease which follows a more or less definite course, exhibits distinctive phenomena, and terminates in certain well-known ways. I have avoided all reference to the large and important subject of the mechanism of convulsions, as this would have entailed a discussion of many physiological problems not yet definitely established.<br><br>A great and increasing interest in the Epileptic has arisen within the past ten or twelve years, an interest which is largely due to the more recent methods of treating Epileptics, as a class, in Special Institutions. The segregation of persons suffering from this disease in "colonies" has therefore permitted of a more complete study of the natural history of the malady than was previously possible.<br><br>My observations upon epilepsy, the results of which are embodied in the following chapters, were based upon the study of one thousand cases, observed partly in my capacity as Visiting Physician at the Colony for Epileptics, Chalfont-St.-Peter, to the Committee and Staff of which Institution I wish to express my thanks and acknowledgments; and partly, in the Out-Patient Department of the National Hospital for the Paralysed and Epileptic, Queen Square. To my colleagues in that Hospital my thanks are due for permission to make use of the notes of some of their cases, more especially in the preparation of the chapter on Prognosis.<br><br>Various portions of the work have already appeared, in somewhat modified form, in Volumes 86, 87, and 88 of the Transactions of the Royal Medical and Chirurgical Society of London.