The author has been hindered by the pressure of other engagements from issuing this volume as soon as he could have wished. Meantime he has had the opportunity of perusing some of the numerous works on the subject here treated which have been called out by the controversy which has of late been so active, both in England and on the Continent: and while availing himself of many valuable hints found in the publications of advocates of Papal Infallibility, he has thought it worth while to examine and answer, with some detail, the arguments brought forward by one writer on the other side. For this purpose he selected the Concilc Général of Mgr. Maret; both because of the attention which that Prelate's position had secured for his work; and because his pages appeared to comprise all the points usually urged by Gallican theologians. The delay which has occurred has therefore helped to render the present volume more complete, and thus, it is hoped, to increase whatever value it may be found to possess.