Plaster is one of the most important of these plastic materials. As a building material, its special quality is its ability to take and retain the form impressed upon it, or upon which it is impressed. As it happens, during the last half-century architects and critics have been paying particular attention to the ‘nature of materials’ and its expression in architecture. There has been a strong insistence on the need for a stone building to demonstrate its stoniness, or a brick building its brickiness. Into such an atmosphere plaster does not fit very well; its essential quality is not its ‘plasteriness’ but its ability to take—and make—architectural forms. Our own development of the uses of plaster, it seems likely, will then be a product of an interest in and a search for form, at least partly for its own sake. This search for form—on the one hand, through the simplification and clarification of shapes that are complex and confusing, and on the other, through the enrichment of shapes that are too simple to interest us—should be our concern here.