Ten years after the announcement of Dudinck's book Philip Labbé (1607-1667) printed a bibliography of bibliographies as a supplement to his Novae bibliothecae specimen (1653).[63] He seems to have regarded this later as a separate publication and has caused some confusion by doing so. On its separate title page the date of this supplement is 1652, but the supplement does not appear to have been issued separately and the title page of the book bears the date 1653. This bibliography of bibliographies is entitled: "Supplementum novae bibliothecae, sive speciminis antiquarum lectionum, coronis libraria. Hoc est, Bibliotheca Bibliothecarum, & Catalogus Catalogorum, Nomenclatorum, Indicum, Elenchorum, &c. quibus Scriptores in quavis arte & professione praecipui, &c. libri ferme omnes, partim editi, partim inediti repraesentantur." Here Labbé has defined the proper contents of a bibliography of bibliographies. He has included very few inappropriate titles in his list of nearly three hundred separately published bibliographies, bibliographies that were still in manuscript, and bibliographies published in non-bibliographical works. There are very few examples of the last category. He is careful about his work. For example, he cites a manuscript biobibliographical dictionary by Alfonsus Ciaconius (Alfonso Chacón, 1540-1599) and gives his authority in Antonio Possevino, Apparatus sacer (Cologne, 1608). Chacón's dictionary was not printed until 1731, and then only as a fragment. Labbé knows Alfonso Barvoet's catalogue of manuscripts in the Escorial; Alfonso García's list of famous Spaniards; Ambrosio Gozzi's biobibliographical dictionary of Dominicans; Andreas Quercetanus's (André Duchesne, 1584-1640) bibliography of French history (three editions are cited); autobibliographies like "Index librorum F. Angeli Rochensis. Romae 1611"; national bibliographies like that for France by Antoine du Verdier; and a classical miscellany like Athenaeus, Deipnosophistae, which scholars then regarded as a bibliography. In other words, Labbé has named examples of varieties of bibliographies that we now recognize. Although he mentions a publisher's catalogue (which he has not seen), he seems doubtful about its pertinence to the task. He comments, for example, on a collective volume in the De Thou library that contained catalogues issued by Plantin, Froschauer, Wechel, and other publishers and says that he is not including it. Labbé's comments are abundant and informative. This first independent bibliography of bibliographies is a commendable piece of work.

Labbé realized that he had hit upon a new and important idea and worked diligently to improve and enlarge his collections. In 1662 he published a sample of his plans for several bibliographies under the title of Sexdecim librorum initia. This consisted of the first eight pages of each of ten bibliographies on which he was working and discussions of six more that he expected to write. The first eight pages of the bibliography of bibliographies extend to Antonius Possevinus (inclusive). A comparison of the complete list of 1653, the sample of 1662, and the book that was finally printed in 1664 is necessarily limited to a portion of the alphabet. In 1653 he cited fourteen names (some of these authors were responsible for several bibliographies), in 1662 he cited thirty-three names, and in 1664 he cited sixty-eight names (including the additions made in a supplementary alphabet). In 1653 he regretted his inability to find a publisher's catalogue issued by Aldus Manutius. In 1662 he reported that he had not found it. In 1664 he cited publishers' catalogues issued by both Aldus Manutius and Aldus Manutius, Junior. In both 1662 and 1664 he made additions to the titles listed under various names, introduced new cross-references, and made improvements in details. As an example of an improvement, note his correction of the name Antonius Bumaldus to Joannes Antonius Bumaldus. This apparently minor change is important because Labbé's arrangement of authors according to their Christian names required him to transfer the name from the letter "A" to the letter "J."

Although Labbé greatly improved his book between 1653 and 1664, he nevertheless published it without incorporating all the additions into the main alphabet and without making full and accurate indexes. Subsequent editions did not completely remedy these serious defects. In 1672, when Labbé had been dead for five years, an anonymous editor combined the additions with the main alphabet, but did not correct errors in the text or improve the indexes. In 1678, the unsold sheets of the 1672 edition were issued with a new title page and a brief appendix containing John Selden's numismatic bibliography. The last edition of the Bibliotheca bibliothecarum was printed at Leipzig in 1682. It is called "enlarged (auctior)," but in a rather extensive comparison I have found only one new title. The German editor removed some of Labbé's comments on Protestant writers but did little more.

Labbé's Bibliotheca bibliothecarum is an alphabetical list according to first names of some eight hundred authors of bibliographies. According to Besterman, it includes about fifteen hundred titles. Labbé's arrangement according to first names causes no difficulty to a modern user because he provides an index of family names. Unfortunately, however, this index of family names is incomplete, and the lack of care in its preparation is evidence that Labbé hurried to get his book to the printer.

Eight subject indexes—only the fourth is not alphabetical—make the Bibliotheca bibliothecarum fully usable. When the reader has familiarized himself with them (and apparently very few have done so), he can understand the book and its value to a scholar. In working with the indexes he will discover that Labbé did not make them complete and reliable. Part of the difficulty in understanding and using the indexes arises from Labbé's old and unfamiliar classification according to men instead of subjects. This classification was firmly established when Labbé wrote and he probably never thought of any other. St. Jerome had called his book by the alternative title "De scriptoribus ecclesiasticis," that is to say, "Ecclesiastical Writers," but it was a bibliography of ecclesiastical literature. A bibliography of astrology was, in Labbé's conception, a list of men who wrote on astrology. He soon ran into difficulties and adopted devices to get around them that show bibliographical method in a transitional state. In "Index I. Practitioners of Various Arts and Sciences (Index Primus. Professores variarum scientiarum atque artium representans)" we find such entries as "Advocatorum Consistorialium, Advocatorum Parisiensis Curiae, Aristotelis Graecorum Interpretum, Arithmeticorum," which we can translate (changing to the nominative case) as "Consistorial Lawyers, Lawyers of the Parisian Court, Greek Interpreters of Aristotle, Arithmeticians." These designations are to be understood as references to as many subjects. "Index II. [Bibliographies of] Nations and Countries" and "Index III. [Bibliographies of] Religions and Religious Orders," which does not include non-Christian religions or heretical sects, give him no trouble. In the fourth index Labbé meets his Waterloo. This "Index IV. Authors Writing on Various Subjects" is awkwardly conceived in terms of the authors but is arranged according to the theological merit of the subjects on which they wrote. It descends from the Virgin Mary to inventions in the following order: (1) writers about the Virgin Mary, (2) [writers about] the Immaculate Conception, (3) writers who were popes, (4) writers who were cardinals, (5) writers who were French cardinals, (6) women writers, (7) writers about heretics, (8) writers on the prohibition of heretical books, (9) compilers of catalogues of manuscripts, (10) compilers of catalogues of ancient and modern libraries and writers on library science, (11) writers on academies, universities, and Jesuit colleges, (12) writers of catalogues and eulogies of individual academies and their faculties, (13) writers on the inventors of things, arts, and sciences. In order to fit his material into this pattern Labbé changes his procedure and writes in an individual entry in No. 10 above: "Manuscriptorum catalogus varias exhibent Antonius Sanderus, Aubertus Miraeus,..." In other words, the subject heading takes the place of a heading in terms of the author. The fifth index lists bibliographers of men who have borne the same name. Anton Sander's book on Antonies is an example. Such works were very popular in Labbé's day and deserved this special attention. The sixth index is a list of bibliographies, which are often autobibliographies, of individual writers and of indexes to their works. The seventh index includes publishers' and booksellers' catalogues. In the somewhat confused eighth index, which again illustrates the difficulty already discussed, Labbé intended to list bibliographies having a proper name in their titles. Here are found books on the Ambrosian and Amsterdam libraries, Labbé's own anti-Jansenist bibliography, and an anonymous catalogue of anti-Jesuitica. He preferred to put the last two bibliographies here and not in the third index, which contained religious bibliographies. He had already set up a category for writers about the Virgin Mary in the fourth index, but he named others in the eighth. I cannot see why he placed writers of dictionaries in the eighth and not in the fourth index, and certainly he should have put writers on chemistry and politics in the first and not the eighth index. These irregularities are difficult to explain. In a search for a subject bibliography a modern reader must turn to the first, fourth, and eighth indexes. He will find a national or local biobibliography in Index II, a biobibliography of a religious order in Index III, a list of works on homonyms in Index V, a bibliography of an individual author in Index VI, and a catalogue issued by a publisher or bookseller in Index VII. The classification is complicated but not altogether unusable.

In the eleven years that passed between the first publication of the Bibliotheca bibliothecarum and its final appearance in 1664, Labbé might have worked out the details more carefully than he did. We can of course pardon some faults because modern bibliographers are more demanding than those of 1664. We may, however, say fine words about these demands and be forced to eat our words when we look later in this essay at the modern bibliographies of Léon Vallée, Henri Stein and the very recent work of Hanns Bohatta and Franz Hodes. While we are mindful of the old saying about those who live in glass houses, we can nevertheless point out inconsistencies, irregularities in procedure, awkward arrangements of materials, and outright errors. The faults to be found in Labbé's book are relatively slight and do not seriously impair its value.

Labbé is inconsistent and irregular in method. He seems to have learned to cite titles in the original languages when he was nearly through collecting them. It was too late to change and furthermore his sources probably often gave him Latin and not the original French or Italian titles. For example, he cites a book by Augustinus Superbus by its Latin title and adds the note "Italicè."[64] In the seventeenth century this was an altogether regular way of citing an Italian title. He also cites the same book with an Italian title. In reading the proof he could have removed the duplication. The article on Augustinus Marloratus seems to have been written before he realized the necessity of bringing the author's name into the first place for the purpose of alphabetizing the entries. He is irregular in regard to critical comment, which the plan of his book did not require. He usually adds none, but see, as exceptions, the remarks on Angelus Roccha, Conradus Gesnerus, Conradus Lycosthenes, and Joannes Neander. It will be noticed at once that all but one of these men are Protestants. In a few instances Labbé gives additional information about the subject of the book that he is citing. For example, he adds a paragraph to the citation of a catalogue of heretical writers compiled by Bernardus Luxemburgensis:

Regarding these men [i.e., heretical authors] ancient writers ought also to be consulted: Philastrius, Augustine, the author of Praedestinati (edited by Sirmondus), St. Epiphanius, St. John Damascene, and others.

This paragraph may indicate that Labbé considered including subjects but did not find a way to do so. Critics of the Bibliotheca Bibliothecarum and among them Adrien Baillet, who should have known better, have called for interpretative and critical comments. They ought to have perceived that such comments, although useful, would have greatly exceeded Labbé's purpose. In all the later history of bibliographies of bibliographies only two men—Gabriel Peignot and Julius Petzholdt—have made a systematic effort to add comments. Labbé does, to be sure, often express his opinion about heretical books, and his warnings have awakened Protestant wrath and have caused Protestant bibliographers to speak harshly of him. He has rarely expressed himself so vigorously as he does in the article "Robertus Cocus" (Robert Cooke, 1550-1615), where he writes:

He wrote Censura Patrum (London, 1623. 4o; 1614. 8o), but it ought to be utterly rejected, along with Rivet's Criticus, Scultetus's Medulla, the outburst of Hottinger, and similar commentaries of the most virulent heretics, by all holding the Catholic faith or it ought to be put far away in the castle of Hell, whence it is forbidden to depart, along with the Magdeburg Centuriators, Mathias Flaccius Illyricus, and the works of others that have been assembled in several volumes. I hear also that a criticism of ancient writers by the same Cooke was published at Helmstadt in octavo in 1655.