''The Life of Reason, or The Phases of Human Progress - Volumes One Through Five'' were first published in 1905 and 1906, by George Santayana (1868-1952) All five volumes of George Santayana's philosophical masterwork exploring the manifestations of reason in life are united in this superb edition. ''The Life of Reason'' begins boldly, with Santayana explaining his concept of reason in great detail. How a mind may embark and progress on applying rational thought to life is explained, and the practical value of such thinking methods are demonstrated. The second volume sees the author questioning whether men can be exhorted to virtuous behaviors without the concept of a creator, heaven, hell or other supernatural concepts. The third volume, Reason in Religion, is an emotional and at times autobiographical account of Santayana's own struggles with faith. Volumes four and five concern science and art, respectively. The basis of artistic expression and its grounding in reasoning is discussed, with chapters dedicated to the visual art of painting and also music.

The Life of Reason, subtitled "the Phases of Human Progress", is a book published in five volumes from 1905 to 1906, by Spanish-born American philosopher George Santayana . It consists of Reason in Common Sense, Reason in Society, Reason in Religion, Reason in Art, and Reason in Science. The work is considered to be the most complete expression of Santayana's moral philosophy . Santayana's philosophy is strongly influenced by the materialism of Democritus and the refined ethics of Aristotle, with a special emphasis on the natural development of ideal ends. The Life of Reason is sometimes considered to be one of the most poetic and well-written works of philosophy in Western history. To supply but a single example, the oft-quoted aphorism of Santayana's, "Those who cannot remember the past are condemned to repeat it," may be found on p. 284 of Reason in Common Sense.

It is remarkably appropriate that this work on aesthetics should have been written by George Santayana, who is probably the most brilliant philosophic writer and the philosopher with the strongest sense of beauty since Plato. It is not a dry metaphysical treatise, as works on aesthetics so often are, but is itself a fascinating document: as much a revelation of the beauty of language as of the concept of beauty. This unabridged reproduction of the 1896 edition of lectures delivered at Harvard College is a study of why, when, and how beauty appears, what conditions an object must have to be beautiful, what makes us sensible of beauty, and the relationship between the object of beauty and the excitement of our sensibilities over it. The presentation throughout this work is concrete and easy to follow, with examples drawn from art, history, anthropology, psychology, and other areas.