A serious and inescapable handicap to the permanent usefulness of Peignot's alphabetical list of many small headings is the rapid obsolescence of technical terms. In some cases we can no longer know exactly what Peignot meant by a particular term and therefore cannot immediately turn to a desired entry. For example, "histoire littéraire" does not mean the history of literature or at least of literature in the sense of belles lettres. In Peignot's use "métaphysique" includes demonology or, as a modern bookseller would say, "occult" books. A specialist in the history of theological studies will know that Peignot's "théologie positive" refers to theology based on God's revelations to man, but two professors in a divinity school did not recognize the term. I am all the more sympathetic with them when I read in Neville Braybrooke's account of Christianity in England the comment on Mr. Billy Graham: "In his way he stood for 'positive theology'."--Cited from _The Commonweal_, LX (1954), 194. Here the term seems to mean "a convincing religion for the man in the street." Peignot does not offer an index of subjects because he believes that his table of contents and his alphabetical arrangement make it unnecessary. This belief is not well-founded because he subdivides many long articles and gives no cross-references and no indication of subdivisions in the table of contents. The bibliography of an individual classical author appears in its alphabetical place in the article "Classiques" (pp. 155-244) and of a religious order in "Ordres monastiques" (pp. 432-437). Without a cross-reference from "Bible" (pp. 26-32) one will perhaps fail to find a list of polyglot Bibles under the heading "Polyglottes" (p. 447). It is not immediately obvious that Peignot has arranged his valuable list (pp. 40-75) of catalogues of public libraries alphabetically according to places. He would have added little to the size of his book by adding cross-references and he would have made it much easier to use. Although Peignot feels the temptation that comes to every bibliographer to wander afield and include works of little pertinence to the task, he apologizes for yielding to it in a prefatory "Nota" to the useful article "Bibliothèques" (pp. 32-135). He includes here such works as Richard de Bury, _Philobiblon_ (a book about collecting books); Claudius Clement, _Musaei_ (a general treatise on library science that contains little bibliographical information); and Louis Jacob, _Traicté des plus belles bibliothèques_ (an excellent account of European libraries in the early seventeenth century). In general, however, Peignot adheres very strictly to his intention of listing only bibliographies.