THE completion last year of the De Ricci and Wilson Census of mediaeval and renaissance manuscripts was for many scholars the fulfillment of a long standing desire to have at hand a complete record of the manuscript holdings in this country and Canada. In the monumental two-volume set, together with the added volume of indices, one may easily locate the codex of some ancient or mediaeval author hitherto buried accidentally, or even purposefully, within the vault of some obscure library or collector's home. For several important reasons the work deserves the approbation of scholars here and abroad. In the first place, the project was a pioneer work. As De Ricci states in his preface, it is the first attempt to record the holdings of the many private collectors throughout the country. Thus, in the case of scholars editing particular works, such a bibliography may conceivably reveal material hitherto overlooked, though perhaps actually close at hand. The limitations, chronological and generic, of the Census are also most commendable. Although the boundary of A.D. 1600 is frequently overstepped, such transgressions do not generally appear unreasonable, since they are usually justified by the nature of the piece described. Likewise the exclusion of Orientalia was a most prudent step, since their listing would have swelled the work out of all practical proportions, besides confusing the aim of the entire project. It is only to be regretted in this connection that the Greek papyri were not included, though their listing has been promised in a subsequent volume. Another commendable feature of the Census is the form of entry employed, which is succinct and well composed, with the salient features consistently described in every case. But where Mr de Ricci appears to have done his best work is in the matter of provenance, former ownership, sales, etc., where his competence and authority are unquestioned. There are, however, a number of grave shortcomings to this monumental enterprise. The Census purports to be a guide to the manuscript holdings in this country and Canada. Therefore, if a scholar wishes to determine the location of the manuscript of any particular author on which he may be working, he will rely unquestioningly on the Census to locate this manuscript, if it is within the territorial limits prescribed by the title. But if, on consulting the Census, he does not find his author or the work in question, he will turn elsewhere: either to catalogues of foreign-held manuscripts, or to what secondary printed sources may be available. Hence, the Census, to fulfill its function adequately, must first of all be exact, since even the slightest error in the formal description of a manuscript means the publication of a false report, consequent misunderstanding, and time and possibly money wasted. Furthermore, if a scholar finds the Census unreliable in one entry, he is not likely to pin much faith on any of the entries, and not only