In the brief span of some 140 pages Pere Gardeil succeeds remarkably well in the simple presentation of the Aristotelian principles of mobile being, quantity, motion, causation, place, time, inanity, the first mover, and astronomical theory. A second section (of some forty-five pages) selects five capital texts from the classic commentary of St. Thomas upon Aristotle's Physics and the full text of his model synopsis of Aristotelian cosmology in the early Paris opuscule, De Principiis Naturae. The translation of the original French work of 1953 has been accomplished with sober clarity and served editorially with a useful index and notes. Its frank, working language should attract both philosophical novice and pragmatic scientist alike and effect their working contact with a classic vision of the universe. --Philosophical Studies.