Towards the end of the Second Empire there was in France no enlightened public opinion on the subject of historical work. Bad books of historical erudition were published with impunity, and sometimes even procured undeserved rewards for their authors. It was then that the founders of the _Revue Critique d'histoire et de littérature_ undertook to combat a state of things which they lightly deemed demoralising. With this object they administered public chastisement to those scholars who showed lack of conscience or method, in a manner calculated to disgust them with erudition for ever. They performed sundry notable executions, not for the pleasure of it, but with the firm resolve to establish a censorship and a wholesome dread of justice, in the domain of historical study. Bad workers henceforth received no quarter, and though the _Revue_ did not exert any great influence on the public at large, its police-operations covered a wide enough radius to impress most of those concerned with the necessity of sincerity and respect for method. During the last twenty-five years the impulse thus given has spread beyond all expectation. It is now a matter of great difficulty to impose on the world of scholars, in matters connected with their studies, or at least to keep up the deception for any length of time. In the case of the historical sciences, as well as the sciences proper, it is now too late to found a new error or to discredit an old truth. It may be a few months, possibly a few years, before a bungled experiment in chemistry or a scamped edition is recognised as such; but inexact results, though temporarily accepted under reserve, are always sooner or later, and generally very soon, discovered, denounced, and eliminated. The theory of the operations of external criticism is now so well established, the number of specialists thoroughly versed in them is now so great in every country, that, with rare exceptions, descriptive catalogues of documents, editions, _regesta_, monographs, are scrutinised, dissected, and judged as soon as they appear. It is well to be warned. It will for the future be the height of imprudence to risk publishing a work of erudition without having first done everything possible to make it unassailable; otherwise it will immediately, or after brief delay, be attacked and demolished. Not knowing this, certain well-meaning persons still show themselves, from time to time, simple enough to enter the lists of critical scholarship insufficiently prepared; they are filled with a desire to be useful, and are apparently convinced that here, as in politics and elsewhere, it is possible to work by extemporised and approximate methods without any "special knowledge." They are sorry afterwards. The knowing ones do not take the risk; the tasks of critical scholarship have no seductions for them, for they are aware that the labour is great and the glory moderate, and that the field is engrossed