The following topics are considered: 1) history of the use of earth as a building material, 2) alteration of earth by water and behavioral effects caused by earthquakes, 2) alteration of earth by water and behavioral effects caused by earthquakes, 3) terminology of the various earth materials used in building construction, 4) extent of the use of adobe throughout the world, 5) contemporary renewal of interest in rammed earth, 6) causes of failure in earthen buildings, 7) earthquake failure, 8) treatment of adobe in restoration, 9) role of chemistry and physics in the study of adobe, 10) influence of adobe on settlement forms and textures.