The concept of reinforcing brittle materials like cement paste, mortar or concrete with fibers has been known since ancient times. For example, baked clay reinforced with straw was used to build mud huts, and mortars for masonry were reinforced with animal hair. The wide variety of fiber types available in the 20th century has led to the development of a specialization in modern concrete technology based upon creating composites incorporating one or more types of fiber into the matrix of cement paste, mortar or concrete. This book summarizes and simplifies the results of a considerable body of research and practical experience with a wide range of fiber-reinforced cementitious composites. This information will prove invaluable to engineers, architects concrete contractors and others working in design, construction or product manufacture who may be unfamiliar with this technology.