The medical writing On ancient medicine is one of the some fifty works transmitted since Antiquity as a part of the Corpus Hippocraticum. The treatise did not attract much attention in Antiquity, the Middle Ages or the Renaissance; probably as a result of Galen's thinking that it was not the work of Hippocrates himself. Nevertheless, this attitude changed soon after Emile Littre placed it in the first volume of his edition of Hippocrates’ complete works. Littre considered the treatise to be a genuine work of Hippocrates, and, ever since, On ancient medicine has been one of the most commented, studied, edited and translated Hippocratic writings. Traditional scholarship has been concerned mainly with three topics. The first is the so-called “Hippocratic Question”, namely the identification of the author with the historical Hippocrates; the second deals with the search for medical and philosophical influences and dependencies between this writing and that of other authors; the third discusses the controversies over attempts to establish the identity of the theorists attacked in this treatise. Mark Schiefsky's book is based on the reworking of his 1999 doctoral thesis. He uses the Greek text established by Jacques Jouanna in his 1990 Les Belles Lettres edition, but provides a general introduction, a translation facing the Greek text, an extensive commentary, two appendices, and three indexes (general index, Greek words, and texts and authors cited). The Greek text offers references to both Littre's and Jouanna's pages, which makes it very user-friendly, and the translation is clear and accurate (where I have checked it). The introduction presents a survey of many of the issues raised by this work, such as the opposition between techne (art, science) and tuche (chance, luck) and the role of accuracy (akribeia) in medicine. It also presents a summary of its content, an overview of the intellectual context in which it was composed and addresses general topics, including audience, date and authorship. Many of these issues are revisited in greater detail in the commentary, as they are meant to be the main supporting evidence upon which to base the claims of the introduction. The discussion about the intended audience of the treatise and its character of oral discourse underlines our lack of knowledge of key topics concerning medical literature, such as who these works were intended for, how accessible they were, and when and why they began to be written and read. Concerning audience and genre, Schiefsky establishes some parallels between On ancient medicine and other Hippocratic writings such as Affections, Art, Breaths, Diseases I and Nature of man. In doing so, he raises some stimulating questions for further research on other Hippocratic writings. Regarding the date of composition, problematic as it always is in connection with anonymous works, Schiefsky argues the treatise was written not much before 420 BC. He may be right, but one of the arguments he bases his conclusion on is the date of composition of the treatises On generation / Nature of child and Diseases IV, which is itself controversial and by no means sure. The thorough and thoughtful commentary is, I think, Schiefsky's greatest contribution. Concerning questions of medical and scientific method, it goes beyond Jouanna's and Festugiere's. Each chapter of the treatise is given a general overview, with attention paid not only to the theoretical and empirical aspects of medicine in early Greece but also to some questions of textual criticism (when they happen to support his interpretation of the passage) and to a minor extent, the author's prose style. Two appendices discussing the relationships between On ancient medicine and medical empiricism, and the affinities and differences between this treatise, Plato, Aristotle and other authors on the imprecision of medicine close the volume. With it Schiefsky has achieved one of the aims he states in the preface: his book is undoubtedly a worthy companion to Jouanna's critical edition and will definitely serve as inspiration to other scholars writing commentaries on Hippocratic writings.