This is unquestionably a very able and carefully-written monograph on a symptom of the greatest practical importance, and one which is present, as the author well remarks, in the majority of diseases. At the same time, headache is so often of such a distressing character, and so obtrusive that it may be the only complaint of the patient, or the only symptom for which he seeks relief, so that any contribution which helps us in our efforts to grasp its meaning, to clear up its association or relation, and diagnose its cause, is most welcome; and it is not too much to say that anyone mastering this complete work should be most familiar with the complex subject of headache. In the search for material, the author has waded through an enormous mass of literature, of which he gives the bibliography and index, and he seems to have extracted therefrom the best essence, which, added to the results of his own observations, based on an analysis of 1,300 cases, contributes to the formation of an admirable treatise.