Galen: Works on Human Nature, Volume 1 is part of the series Cambridge Galen Translations. It is the second book to be published in the series, after Galen: Psychological Writings, and it contains only one text, Galen’s treatise on Mixtures in three books. Like some of the translations in Psychological Writings, Singer’s translation is a reworked version, with expanded notes and commentary, of one that appeared in his 1997 volume Galen: Selected Works, in the Oxford World’s Classics series. That volume, which made many of Galen’s most intriguing works accessible in English to students and scholars alike, has sadly been out of print for so long that my own tattered copy resides in a plastic zipper bag where I preserve it from decay. While it is helpful to have the authoritative, scholarly translations in the Cambridge Galen Translations series, their price prohibits their use as classroom texts, and a reprint of Galen: Selected Works is still desirable.

Van der Eijk’s introduction to this translation of Mixtures not only clarifies the treatise’s main medical and philosophical themes, but also covers points important to the historian, beginning with the editor’s case for the centrality of Mixtures to Galen’s body of work. Although it is not one of Galen’s longer, monumental treatises, like The Usefulness of the Parts or The Method of Healing, nevertheless Galen considered it part of the ‘core curriculum’ he prescribed for students seeking to learn medicine, and it was part of the canon of sixteen treatises taught in Alexandria in late antiquity. In discussing the audience for this treatise, van der Eijk appropriately draws attention to the social context for which it was written – several signs show that it served a practical, pedagogical function alongside live, face-to-face training in clinical medicine. Other topics covered in the introduction include the influence of Aristotle on Galen’s work (this treatise is unusual in its unambiguously positive evaluation of Aristotle), Galen’s teleological stance as expressed here and in other treatises, the intellectual history of the theory of mixtures and the treatise’s influence on the medical traditions of later centuries.

Mixtures is a discussion of the essential qualities of hot, cold, wet and dry, how we can discern and measure these mixtures in patients and how we can use the mixtures of different foods and drugs to correct imbalance. While Hippocratic theory connected these qualities to the four humours, and Galen accepted humoral theory and elaborated on it, there is little discussion of humours in this treatise (on Galen’s humoral theory the recent book of Keith Andrew Stewart, Galen’s Theory of Black Bile, Brill 2018, is now fundamental). Its best-known passages link the essential qualities to personality traits, physical characteristics and race. Less well-known but equally striking is Galen’s discussion of how to measure the qualities, especially heat; he thought that the skin of the inside of the human hand was specially adapted for that purpose. Galen claimed to be able to distinguish fine gradations of heat by touch and to be able to remember a patient’s heat profile for years, a claim that as a mother who hates thermometers, and who has always measured her children’s temperatures by hand, seems less extraordinary to me than the editors of this volume find it.

Singer’s translation is well-supplied with notes that clarify, set context and render this treatise accessible while also addressing questions of language and influence interesting mainly to experts. Among this edition’s more user-friendly features are the headings that describe the contents of each chapter; summarizing Galen’s prolix and often meandering discussions succinctly is no easy feat, and even seasoned Galen scholars will appreciate the effort. Cambridge Galen Translations offers no Greek text, only translation, but the abundant notes compensate somewhat for this, as well as the Greek-English glossary and the index of Greek words among the supplemental apparatus. Many will also find the list of titles, abbreviations and editions of all of Galen’s works convenient, although it is based on the list by Fichtner that is always available, open-access and up to date, on the Corpus Medicorum Graecorum website. The text indicates page numbers in both Kühn’s and Helmreich’s editions of Mixtures in the margins.

We eagerly await more translations in this high-quality series, including the first five books of On Simple Drugs, currently in preparation by John Wilkins, which will begin to open the huge black box of Galenic pharmacology to general scholarship.