Joseph Bobik offers a translation of Aquinas's De Principiis Naturae (circa 1252) and De Mixtione Elementorum (1273) accompanied by a continuous commentary, followed by two essays: "Elements in the Composition of Physical Substances" and "The Elements in Aquinas and the Elements Today." The Principles of Nature introduces the reader to the basic Aristotelian principles such as matter and form, the four causes so fundamental to Aquinas's philosophy. On Mixture of the Elements examines the question of how the four elements (earth, air, fire, and water) remain within the physical things composed...

Many great thinkers have wrestled with the topic of evil. St. Thomas Aquinas's disputed question On Evil merges as the longest and most comprehensive study on the subject of evil available. This long-awaited translation is based on the critical edition of the Latin text published by the Leonine Commission in 1982. The disputed question De malo (On Evil) was first presented as a series of oral debates at the University of Paris (1263-1272?) and subsequently recorded in the form in which it now appears. The length of the work and the thoroughness of the treatment is eloquent testimony of the...