Approximately 71 per cent of the earth's surface is covered by water, 97 per cent of which is contained within the five interconnected oceanic zones spread across the surface of the Blue Planet. This humble substance is no mere foil for terrestrial topography but is rather essential for the emergence and sustenance of life as we know it. It is therefore little wonder that scholars in the humanities have begun to situate water at the centre of their inquiries into the histories and cultures of human and non-human animals.

The conceptual currents radiating out from the so-called Blue Humanities have found particularly firm purchase in scholarship on ancient Greece and Rome. The majority of this work has centred on the practical importance of the sea to the economies and societies of the Mediterranean Basin (e.g. P. Horden and N. Purcell, The Corrupting Sea (2000); C. Broodbank, The Making of the Middle Sea (2013); E. Mataix Ferrándiz, Shipwrecks, Legal Landscapes, and Mediterranean Paradigms (2022)). A smaller, but no less radical body of scholarship, has taken a less historicist route, and focused instead on the imaginative engagements by ancient authors and artists with the maritime world and the ecosystems it generates and supports (e.g. M.C. Beaulieu, The Sea in the Greek Imagination (2015); E. Kneebone, Oppian's Halieutica (2020)).

Georgia L. Irby's Conceptions of the Watery World in Greco-Roman Antiquity makes a timely and original contribution to this rapidly expanding domain of thought and inquiry by reorienting our angle of vision towards the epistemological status of the aquatic through an interrogation of ancient attempts to explain water from scientific, philosophical and religious perspectives. This is the first instalment in a two-volume series preceding Using and Conquering the Watery World in Greco-Roman Antiquity (2021). In Conceptions, as its title suggests, Irby focuses solely on intellectual engagements and entanglements with water, seeking to illuminate the manifold ways in which liquid landscapes were understood and imagined by ancient philosophers, scientists and mythographers.

The book is divided into three complementary parts. Part One (‘Interpreting the Watery Framework’) explores attempts to conceptualise and categorise both aquatic (e.g. rivers, seas) and semi-aquatic (e.g. islands, springs) phenomena within a range of cosmogonic, physical and philosophical frameworks. Part Two (‘Explaining Watery Phenomena’) interrogates the explanations offered for conditions and events associated with water, focusing particularly on weather and disease. Part Three (‘Imagining the Watery World’) turns its attention to the sizeable landscape of aqueous imaginaries and charts a course through the litany of gods, monsters, creatures and forces that asserted their presence in maritime contexts in ancient art and literature.

The picture of water that emerges from Conceptions is one of a simultaneously ‘polymorphic’ and ‘metamorphic’ (228) entity that both transformed and was transformed by the unstable currents of ancient thought. It was water, I. shows, that, on the one hand, ‘fired the ancient imagination’ (23), rearing its head as, among other things, a fundamental building block of the cosmos, a technology of cartographic organisation, a balancing foil for the terrestrial landscape, and more. It was, however, not merely a thing to think about, but likewise a tool to think with: ‘a central component in how ancient thinkers viewed and interpreted their world, providing a prism through which to observe and consider natural philosophy and watery phenomena’ (192).

Conceptions is especially remarkable for its pioneering embrace of interdisciplinarity. I. not only spans a wide range of subjects and methodologies from within the ambit of Classics but likewise wades into the waters of geography, hydrology, history of science, and so on. She does so, moreover, while avoiding the positivist pitfalls lying in wait for the clumsy intellectual historian, noting from the outset that her interest is not in whether the ancients were ‘right’ or ‘wrong’ in the view of modern science. She rather focuses our attention on the particular kinds of questions and responses developed by ancient thinkers and what this says about the unique cultural and intellectual context of antiquity.

The book is not, to be sure, without its weaknesses. I., for example, is clear that she has relied primarily on literary sources as the basis of her discussion. There are, however, in spite of this uneven weighting, several important texts that are not given a fair hearing. One example of this is the substantial extant corpus of Greek periploi (i.e. coastal geographies). I. makes incidental mention of some such texts but does not afford them any sustained or systematic discussion. This is a non-trivial oversight that results in the maritime coastline as a unique space of terraqueous interchange being sidelined in the discussion of land and water in ch. 3. This is despite the fact that works like Dionysius of Byzantium's Anaplous of the Bosporus engage creatively with the theme of the symbiotic relationship between the terrestrial and the aquatic that animates this section of the book.

These shortcomings do not detract, however, from the importance and originality of I.'s offering. This is an engaging and accessible work that does the long-overdue work of tracing the history of ancient epistemological engagements with aquatic environments. The treatment of practical human engagements with the watery world (e.g. baths, aqueducts, lighthouses) in Using and Conquering is a necessary complement to the intellectual history set out in Conceptions. These should now both be standard reading for students and scholars of maritime history and the environmental humanities.