Explains what revivalism, rationalism, eclecticism, and functionalism meant to those who practiced them, explores the influence of the other arts and sciences on architectual theory, and analyzes notions that are commonly used in discussions about modern architecture. Infused with a deep sympathy for the 19th century, this text suggests that many 19th century ideas can be of real value to practising architects, particularly now that technology has made it possible to put them into effect properly. This second edition should be of interest not only to those who specialize in architecture and have read the standard work of Hitchcock, Giedion, Pevsner, and Joedicke - but also to those with a general interest in modern history and the philosophy of art.