Certain inorganic materials have significant advantages over some construction materials in energy costs of production and fabrication but are weak in tension and against impact. These weaknesses can be alleviated by the use of reinforcing fibers, the limiting factor governning their use being the cost. One attractive, comparatively low cost fibrous additive is wood fiber. The article discusses what composites are and how they work; wood fiber-cement composites and wood fiber-plaster of Paris composites; and the chemical and physical properties of such composites. -- AATA