This volume is one of the most valuable additions to the Dumbarton Oaks Medieval Library and a must-have for the library of any scholar of high medieval literature or intellectual culture. It follows close on the heels of Wetherbee's edition of the literary works of Alan of Lille, also for Dumbarton, and the two make a distinguished pair.  In this edition Winthrop Wetherbee brings together, for the first time in a single volume, the collected poetic works of Bernardus Silvestris (Cosmographia, Mathematicus, De gemellis, and De paupere ingrato) and he translates the latter three for the first time into English as "The Astrologer," "The Twins," and "The Ungrateful Pauper." Cosmographia is well known as one of the finest allegorical treatments of God's relationship to Nature made in the twelfth century before Alan of Lille's De planctu naturae and Anticlaudianus, but the latter three shorter poems--all examples of ancient rhetorical controversiae--have received insufficient scholarly attention. Prof. Wetherbee was an obvious choice for the task of bringing together Bernardus's collected poetry, as he is (alongside Peter Dronke) one of the greatest living scholars of medieval Latin literature and had already published a translation of the Cosmographia in 1973. 
Like all volumes in the Dumbarton Oaks Medieval Library, this one includes editions of the Latin texts, with English translations on the facing pages. Wetherbee has opted for prose translations of the Latin verse, a wise choice given how difficult it can be to unpack the meaning of Bernardus's tightly woven poetry. The orthography of the Latin has been "restored" (263) to classical spelling, an unnecessary and misleading editorial policy that does not reflect any manuscripts of the text. None of the editions are new or critical, in the strict sense, but represent Wetherbee's careful reading of older editions, presented with occasional emendations. Wetherbee's edition of Cosmographia is based closely on that of Peter Dronke , with minor changes based on his own close knowledge of the manuscripts. Wetherbee himself noted in a review of Dronke's edition that a truly critical edition, taking account of all manuscripts (which Dronke's does not), is still needed.  That was in 1980, and remains true. Wetherbee bases his edition of Mathematicus on the 1993 St. Ottilien edition , with a few readings coming from the 1994 edition of Teresa d'Alessandro.  Finally, both De gemellis and De paupere ingrato were edited by Robert Edwards in 1993, and Wetherbee uses his edition of both, with only limited emendation. 
In a brief introduction of ten parts, Wetherbee outlines the life and career of Bernardus, his intellectual milieu, and the design and meaning of the Cosmographia, while providing summaries of the other three poems. He presents the Cosmographia as a "masterwork" and a "radically original" (xiv) example of the teaching on nature and grammar practiced in Chartres and Paris in the first half of the twelfth century, especially insofar as it serves as a commentary on Plato's Timaeus read through Christian eyes. Mathematicus is based on one of the Declamationes of Pseudo-Quintilian, and Wetherbee describes it as a curious union of two popular topics in the twelfth-century schools: legal rhetoric and an extremely fatalistic sort of astrology. Wetherbee devotes only two pages of his introduction to the shorter De gemellis and De paupere ingrato, which are also based on Roman declamationes (respectively, Pseudo-Quintilian again and Seneca the Elder). Granted, they hardly deserve the attention given Cosmographia, but given that this volume will likely become the official entry for generations of students to Bernardus's poetic works, Wetherbee ought to have provided more on these controversiae, even if it meant simply paraphasing the study by Robert Edwards.
At the end of the volume, Wetherbee provides a useful bibliographical essay on the major manuscripts and older editions of each of the four texts, and his justifications for which ones he follows. He also indicates the variant readings he is following in comparison with other editions and important manuscripts of each text, followed by notes on the translations, a bibliography, and an index of names. The notes to the Cosmographia are far briefer in this volume than in his 1973 translation, but extensive notes are no longer necessary here, since interested students have long been able to turn to Brian Stock's Myth and Science in the Twelfth Century: A Study of Bernard Silvester (Princeton, 1972), which appeared while Wetherbee's first translation was in press, or more recently to Mark Kauntze's Authority and Imitation: A Study of the Cosmographia of Bernardus Silvestris (Leiden, 2014).
I imagine that many readers of this review will want to know if they should buy this new volume when they already own a copy of the 1973 translation of Cosmographia, so for the rest of this review, I will compare some of the significant differences in translation between the 1973 and 2015 versions. As the translations of the other three poems are the first in English, I cannot draw any comparison, but simply remark that they are usually clear and elegant.
The new translation of Cosmographia offers few significant changes from Wetherbee's 1973 translation. Wetherbee now retains Bernardus's Latinized Megacosmus and Microcosmus throughout, in place of the artificially Grecized Megacosmos and Microcosmos of his 1973 translation. He has also reversed the order of the dedication and summary, now placing the summary first, but that does not affect the sense of the work. In a few cases Wetherbee has corrected outright errors from the first translation, such as skipping the word feliciter at the end of the summary (66, 1973 ed., and now rendered as "appropriately," 5). Some changes are debatable: in this new translation, Wetherbee reads the Edenic garden of Physis as "Gramision" (133), following Dronke's edition, rather than his former "Granusion" (110-111, 1973 ed.). A case could be made for either reading based on the interpretation of minims and the sense of the surrounding passage. Wetherbee also provides new translations based on a revised punctuation of the text, as we find at the very end of the work (Microcosmus 14, line 171), now punctuated Influit ipsa sibi Mundi Natura; superstes, but which Wetherbee in 1973 rendered without the semicolon: "The nature of the universe outlives itself, for it flows back into itself..." (126, 1973 ed.). With the semicolon, the line reads more elegantly, "The life of the Universe flows back into itself; it survives itself..." (181). (I do wonder why Wetherbee now translates this Natura as "life" rather than "Nature," as he has done everywhere else in the work, particularly when Natura is capitalized.) Wetherbee has made many small changes and corrections to the lengthy catalogues of plants and animals in Megacosmus 3, such as now recognizing galanga as galingale (53) rather than galbanum (83, 1973 ed.). However, it is surprising that Wetherbee does not recognize that the word species in this section (Megacosmus 3, line 323) must surely be "spices" rather than "species" (53).
From the start of the new translation we can see that, in many small ways, Wetherbee's style has matured and simplified since 1973. In the opening line of Megacosmos 1, Bernardus calls Silva congeries informis, a phrase which Wetherbee once translated as "a formless chaotic mass" (67, 1973 ed.), and now simply as "a formless pile" (9). Yes, it is less poetic, but it is also more accurate and does not introduce the potentially complicating technical concept of chaos. A more grounded and earthly conception of Silva, Hyle, and Nature pervades the new translation, as is only fitting. For example, Hyle is now called "the primal ground of bodily form" (17), where she was once "the primary basis of formal existence" (70, 1973 ed.). While I usually appreciate the relative simplicity of Wetherbee's new translations, at times his English is so spare as to veil Bernardus's meaning. For example, in Mathematicus, line 54, Wetherbee translates Frena dabit ratio rebus et ingenio as "reason will govern his wealth and his ready mind" (186-187), when the sense requires a more literal translation of bridling, curbing, or checking for Frena dabit.
Wetherbee also improves on his earlier translation of Cosmographia by introducing a greater precision of relationships between the characters by now calling Noys "his [God's] unfathomable Mind" (9) rather than simply "the unfathomable mind" (67, 1973 ed.). As the nature of Noys is a central element of Bernardus's cosmology and theology, Wetherbee's changes to her description are vital for the reader dependent on the English. So also in Megacosmus 2, Noys now identifies herself as "the deeply considered reason of God" (13), whereas in 1973 Wetherbee called her "the consummate and profound reason of God" (69, 1973 ed.). Such changes are small on the surface but provide further evidence of how Wetherbee has subtly rethought the presentation in English of these complex Latin personifications. I could go on for ages in this vein. What is important is that Wetherbee appears to have carefully reviewed every line of his 1973 translation and kept much of it, not out of laziness but because it was still sound. Most of the changes made improve on his first translation, and further recommend the new edition.
The Latin and English texts are nearly impeccable. The only typographical errors I found were phyisicam in the introduction (x), and an improperly capitalized "Since" in Mathematicus (187, line 32). The volume would also be more useful if the running header or margin of Cosmographia indicated the current book of Megacosmus or Microcosmus, as scholars using the work frequently need to search by book. These complaints are small when compared with the immense utility of having in one volume facing Latin-English texts of all of Bernardus Silvestris's poetic works, not to mention the affordability of the volume and the improvements Wetherbee made to the translation of Cosmographia.
1. Alan of Lille, Literary Works, ed. and trans. Winthrop Wetherbee; Dumbarton Oaks Medieval Library 22 (Cambridge, MA: Harvard University Press, 2013).
2. The Cosmographia of Bernardus Silvestris, trans. Winthrop Wetherbee (New York: Columbia University Press, 1973).
3. Bernardus Silvestris, Cosmographia, ed. Peter Dronke; Textus minores 53 (Leiden: Brill, 1978).
4. Speculum 55:2 (1980), 337-9.
5. Bernardus Silvestris, Mathematicus, ed. and trans. Jan Prelog, Manfred Heim, and Michael Kiesslich (St. Ottilien: EOS, 1993).
6. Bernardus Silvestris, Mathematicus, ed. and trans. Teresa d'Alessandro, in Tragedie latine del XII e XIII secolo, ed. Ferruccio Bertini (Genoa, 1994), 9-159.
7. Both are edited by Robert R. Edwards in "Poetic Invention and the Medieval Causae," Mediaeval Studies 55 (1993), 183-217.