The thirteenth-century logician Lambert of Auxerre was well known for his Summa Lamberti, or simply Logica, written in the mid-1250s, which became an authoritative textbook on logic in the Western tradition. Our knowledge of medieval logic comes in great part from Lambert's Logica and three other texts: William of Sherwood's Introductiones in logicam, Peter of Spain's Tractatus, and Roger Bacon's Summulae dialectics. Of the four, Lambert's work is the best example of question-summas that proceed principally by asking and answering questions on the subject matter. Thomas S. Maloney's translation of Logica, the only complete translation of this work in any language, is a milestone in the study of medieval logic. More than simply a translation, Maloney's project is a critical, comprehensive study of Lambert's logic situated in the context of his contemporaries and predecessors. As such, it offers a wealth of annotation and commentary. The lengthy introduction and extensive notes to the text explain the origin, theoretical context, and intricacies of the text and its doctrines. Maloney also addresses the disputed issues of authorship, date, and place of publication of the Summa Lamberti and makes available to the English-only audience the French, German, and Italian secondary sources-all translated-that are needed to enter the discussion.

Early in the 1240s the University of Paris hired a recent graduate from Oxford, Roger Bacon by name, to teach the arts and introduce Aristotle to its curriculum. Along with eight sets of questions on Aristotle's natural works and the "Metaphysics" he claims to have authored another eight books before he returned to Oxford around 1247. Within the prodigious output of this period we find a treatise on logic titled "Summulae dialectices," and it is this that is here annotated and presented in translation. The book is unique in several respects. First, there is the breadth of its sources. Not only do we find explicit reference to the usual authors such as Aristotle, Plato, Boethius, Porphyry, Cicero, and Priscian, we also find unexpected reference to Augustine, Bernardus Silvestris, Donatus, Terence, and Themistius, along with mention of the Muslim philosophers Algazel and Ibn Rushd. Second, it is clear that Bacon is drawing on or reacting to an extraordinarily wide variety of medieval sources: Garland the Computist, Hugh of St. Victor, Master Hugo, Hugutius of Pisa, Isidore of Seville, Nicholas of Damas, Nicholas of Paris, Richard of Cornwall, Robert Kilwardby, Robert of Lincoln, and Robert the Englishman. Third, it unexpectedly presents a full-blown treatment of Aristotle's theory of demonstration. And finally, Bacon reveals a highly unorthodox view of the signification of common terms. Bacon, here, takes his students and us deeper into medieval sources and controversy than any of his rivals do.