Mabillon’s work forms a magnificent monument not only to the learning, diligence, and literary skill of its writer, but to the enormous value of the services rendered, during a number of centuries, by the monks of his Order, in the preservation of literature from the ravages of barbarism and in the development of scholarship. Mabillon also makes clear the lasting importance of the original initiative given to the literary labour of the Benedictines by the Rule of their founder. An important portion of the material upon which Mabillon’s treatise was based, was collected during a series of journeys made by him in company with his brother under the instructions first of the great minister Colbert, and later, of Le Tellier, Archbishop of Rheims, for the purpose of examining or of searching for documents relating to the royal family and of procuring books for the royal library. The first of these journeys, undertaken in the year 1682, was completed entirely within French territory and was entitled _Iter Burgundicum_. The second covered a considerable portion of South Germany and Switzerland, and is known as the _Iter Germanicum_. The third was devoted to Italy, and is described under the title of _Iter Italicum_; while the fourth investigation was made in Alsace and Lorraine, and the record is entitled _Iter Literarium in Alsatiam et Lotharingiam_. The plan of the journeys involved a thorough ransacking of as many libraries as they could secure admission to, the libraries being, with but few exceptions, contained in the monasteries. The immediate result of these journeys was the addition to the royal library of some three thousand volumes, chiefly collected in Italy, and the later result, the publication of the records above specified, which form a most valuable presentation of the condition of the monastic collections in the seventeenth century, and which give in their lists the titles of a considerable number of valuable works which have since entirely disappeared.