In this innovative book, Gloria Frost reconstructs and analyses Aquinas's theories on efficient causation and causal powers, focusing specifically on natural causal powers and efficient causation in nature. Frost presents each element of Aquinas's theories one by one, comparing them with other theories, as well as examining the philosophical and interpretive ambiguities in Aquinas's thought and proposing fresh solutions to conceptual difficulties. Her discussion includes explanations of Aquinas's technical scholastic terminology in jargon-free prose, as well as background on medieval scientific views - including ordinary language explanations of the medieval physical theories which Aquinas assumed in formulating his views on causation and causal powers. The resulting volume is a rich exploration of a central philosophical topic in medieval philosophy and beyond, and will be valuable especially for scholars and advanced students working on Aquinas and on medieval natural philosophy.

‘Frost’s volume, as a whole, is a work of the finest scholarship. She demonstrates a thorough knowledge of the material, is well acquainted with the relevant primary and secondary sources, and explains everything to the reader in a clear, straightforward manner with a number of helpful illustrations.’

Gregory T. Doolan Source: The Thomist

‘Frost’s account of Aquinas on causation is exemplary. It is written with great clarity and avoids jargon … Frost’s book is now the definitive 'go-to' book for anyone who wants to get a detailed understanding of Aquinas on efficient causation. I would add that it is a book that any philosopher interested in causation should read … not only as an excellent essay in the history of philosophy but also as a distinguished contribution to philosophy as such.’

Brian Davies Source: Journal of the History of Philosophy

‘Its rigorous and uniquely holistic analysis of Aquinas’s theory of natural efficient causation makes it an invaluable scholarly resource. Moreover, Frost expresses this scholarship with remarkable clarity: her writing is lucid and stocked with vivid examples, and she always lays out the basics before going in depth, which makes the book also well suited to students not yet versed in Thomism. Frost’s work should grace the shelves of any scholar and professor interested in Aquinas’s natural philosophy.’

Francis Feingold Source: Speculum