One of the most famous sayings of Aristotle is that human beings are political animals by nature. To live in a political society is essential not only for survival but also for living a good, happy life. It is only in political societies that humans can realize their human nature. The political community is therefore prior to the individual: individual citizens are parts of a whole. Aristotle's naturalistic and teleological account of the political community raises several questions, still debated by modern scholars. What exactly does “by nature” mean in Aristotle's slogan? In what sense is a political community natural? Are citizens really mere parts of society or can the part also live separate from the whole? Many such questions also occupied medieval readers of Aristotle's Politics. Though not part of the regular curriculum, the text was carefully studied after the appearance of William of Moerbeke's translation in the 1260s.

Toivanen's excellent book provides an in-depth examination of this commentary tradition, to which are added some other works closely related to it such as Thomas Aquinas's De regno ad regem Cypri and Giles of Rome's De regimine principum. The book is organized thematically rather than chronologically. In six chapters Toivanen discusses terminological issues; the biological basis of human sociability (where self-preservation and the preservation of the species play a key role); the role of the political community in attaining a happy life in the Aristotelian sense (and whether everybody can attain that status); the importance of language in attaining this goal (without language we won't be able to talk about what is just and unjust); the similarities and differences between humans and animals (and whether social animals such as bees can also be called political, and if so in what sense); the place of humans between beasts and gods (and whether a human life outside political society is possible). Together these chapters offer a comprehensive and detailed examination of the medieval debate. Prominent voices are Albert the Great, Thomas Aquinas, Giles of Rome, Peter of Auvergne, Walter Burley, and Nicholas Oresme, but Toivanen also pays substantial attention to many lesser-known figures as well as some anonymous commentators, whose works he had to read in the manuscripts. Given the theme of the book, well-known political thinkers such as Dante and Marsilio of Padua don't play a prominent role, for this book is not about political institutions, the ideal political institution, the relationship between the secular power and the Church, or the nature of political power.

The book is presented as a philosophical study in the analytical tradition, which means that its main focus is on arguments. Toivanen dissects carefully chosen texts to lay bare their premises, conclusions, hidden assumptions, theoretical commitments, terminology, and conceptual connections between positions. This is one of the strong points of the book. Consequently, it does not pay much attention to historical influence or chronological issues. The self-imposed chronological limits prevent Toivanen from saying much about long-term developments: can we see changes within this period, and what was its impact on Renaissance and early modern discussions? Some tentative suggestions are made—for example, that medieval authors tended to emphasize the voluntary aspect to live in a political society, or that metaphysically the human essence is not (wholly) dependent on such a life, but Toivanen carefully refrains from making claims that his texts don't support. Also, he leaves it to the reader “to decide” (360) in what way these medieval debates can have a bearing on contemporary issues. If the commentaries had any impact on their own times can also be doubted: hardly any connection can be made between these commentaries and the social-political world in which they were written. Apart from an occasional glimpse, many of these discussions, by the nature of the genre, don't seem to reflect societal or political developments of late medieval society.

What the book does offer is a careful and skillful analysis of the arguments which these texts contain. The conclusions that these medieval authors reached might perhaps not strike the reader as surprising or innovative. But they testify to an ongoing engagement with important questions about the human condition. As such, Toivanen's book is a fine contribution to our knowledge of an understudied corpus of texts.