The Categories had a peculiar destiny in comparison with other parts of the corpus Aristotelicum: it was commented upon with next to no interruption from the time it was written until the seventeenth century. This was the case both in the Greek-speaking world, where the Neoplatonists gave detailed exegeses of the work (think of how Simplicius’ commentary represents an accomplishment in this regard) and in the Latin-speaking West where, almost on its own, this work summarised Aristotelian thought during the first centuries of the Middle Ages. When confronted with such a mass of interpretations, it is sometimes helpful to return to the text, and only it. This is what this Italian book, which stems from a seminar that was held at the University Ca'Foscari in Venice from 2005 to 2007, invites us to do.

The volume offers a new Italian translation of the text, a line-by-line commentary, a study of the structure of the treatise by C. Natali, and two additional articles, the first on quantities, the second on the theory of truth. Each of the fifteen chapters of the treatise – the particularly rich chapters 5, 6 and 7 have been divided into two – has been translated and commented upon by a different exegete. The book aims to be a didactical instrument – a companion to the reading and interpretation of the text. It is a collective work: each of the twelve contributors comments on the text in his or her own way with his or her own bibliographical references. There is a section of commentary after each chapter or half chapter. Although it slices up the reading of the treatise, this editorial choice gives the commentary a central position in that it is not squeezed into foot- or endnotes, but is put in continuity with the text. By these various aspects and the clear priority given to the commentary and explanation of the treatise, it differs from other recent contributions to the study of the Categories more focused on textual issues (the new edition and translation by R. Bodéüs [2001]) or on translation issues (in particular in French – the translation by F. Ildefonse and J. Lallot [2002] and that by P. Pellegrin and M. Crubellier [2007]).

The first aim of the commentary is to explain what Aristotle means in the treatise. In this sense, the commentary is not so much philological or lexical (as was, for example, that of Ildefonse and Lallot, who are very sensitive to the language of Aristotle) as it is pedagogical, in the noble sense of the term. It seeks to make accessible a text that remains very complex, despite the fact that it was traditionally studied at the beginning of the course of studies (the Neoplatonic school studied it just after reading the Prolegomena to philosophy and Porphyry's Isagoge). This aim is successfully achieved, as the volume offers welcome help in reading the text and highlights on many occasions its doctrinal richness.

Commenting upon the Categories is a difficult exercise because the interpretations, both ancient and recent, are numerous. With the exception of M. in her commentary of Chapter 6, the contributors have chosen to refer very little to late ancient commentators (contrary to the choice that was made, for example, by J. Barnes in his commentary to Porphyry's Isagoge [2003]). In some cases, the reading that is offered is contrasted with modern canonical interpretations (Ackrill, Oehler, Frede, etc.) – a particularly successful example of this is provided by B. Botter for Chapter 2. Logical formalisation is rarely used. Most contributors have chosen to transliterate the quoted Greek words and expressions (note that the volume does not contain the Greek text of the treatise). The variants of the text are rarely discussed, only when they determine the interpretation of the passage: for example P. Fait discusses the reading τῆς οὐσίας in 1a2, which has been deleted by several contemporary editors and translators, on the basis of a passage of Simplicius (In Cat. 29.28–30.5) which states that, according to Porphyry, when Boethos of Sidon gave a detailed commentary of this passage, he did not mention this expression.

The two additional studies, by J. Barnes, ‘Aristotelian Quantities’, and W. Cavini, ‘Vero e falso nelle Categorie’, are both remarkable. The discussion by J. Barnes of the issue of quantity examines several theoretical problems related to this understudied category. The unity of this category may be questioned and it is subject to the fundamental problem of categorical overlapping (i.e. to debate about its belonging to one or the other category, and about one item's belonging to several categories). Many quantitative properties are relational: ‘large’, ‘small’, ‘many’ and ‘a little’ are not quantified but relatives (see 5b15 ff.).

It seems superfluous to remind the reader of the fundamental role of the Categories, from both a historical and a theoretical point of view. Historically, this text, which was so often commented upon, was one of the reference writings of philosophical thought for a millennium, say from Porphyry to the rediscovery of Aristotle's Metaphysics in the Latin West, and it gave this period a large part of its conceptual vocabulary. It was also often used by theologians in their effort to find a rational formulation of Christian dogma. Doctrinally, many philosophical problems – essence, the ontological status of universals, individuation, the real existence of relations – were contemplated, in the Aristotelian tradition, on the basis and with the help of the conceptual tools of the Categories. While this volume does not aim at contributing to the study of the historical role of the work, it definitely invites one to consider the philosophical importance of the Categories, by facilitating an accurate reading of the text.