PREFACE: FOR many years past I have had in contemplation the preparation of a book in which building materials should be described and their present methods of manufacture explained. As time went on, the need for such a book a modern book at a moderate cost was more and more forcibly brought home to me,owing to the extreme difficulty which my students found in obtaining reliable and recent information. In undertaking to prepare such a book I knew the task would be no light one, and it has proved even more arduous than I had anticipated. For more than eighteen months every moment which I could spare has been devoted to collecting and arranging notes, inter- viewing manufacturers, inspecting works, and to a lesser extent to actually writing the book which is now about to see the light. Atone time the notes alone more than filled a large drawer made for double-elephant paper while hundreds of letters and post-cards have been written for the purpose of obtaining at first-hand the information which is contained in the volume often compressed into tabular form. Wherever possible, too, I have seen things for myself, visiting the slate quarries of North Wales, the stone quarries of Somerset, Gloucestershire and Rutland- shire, the iron and steel works of Middlesbrough, the terra-cotta works of Ruabon, Portland cement works at Greenhitheand near Leamington, and numerous brickfields and lime-kilns, and important manufacturing premises, in and around London. Wherever I have visited, and however searching my enquiries have been, I have been received with the utmost ...