A profoundly organic view of man in nature, the concept of ''ages of man'' made itself felt in nearly all forms of medieval discourse--sermons, Bible commentaries, moral and political treatises, encyclopedias and lexicons, medical and astrological handbooks, didactic and courtly poems, and even stained glass windows. J.A. Burrow's analysis ranges over the many manifestations of this idea, and considers the ways in which such ideas of natural order entered into medieval writer's assessment of human nature.