This is a reference book. Although it might conceivably be read in the order in which the subjects appear it was designed to be consulted subject to subject as one uses a dictionary or encyclopedia. To facilitate quick identification and location of building materials, characteristics and problems they are first listed in the table of contents, repeated in the chapter headings and listed in the index. In addition to describing how building materials respond to environmental stresses in terms of their mechanical, electrical, chemical and thermal properties, brief references to their normal behavior and a comparison of various material characteristics has been included. Most of the information gathered and presented here represents the contemporary developments of ancient building lore. The increasing importance of renewal, rehabilitation, retrofit and restoration is placing added importance on material behavior. A separate and distinct field of building science is emerging as increasingly sophisticated instruments are linked to the growing ability and decreasing costs of computer analysis. This book describes one segment of a new building science-that of building diagnosis.