Cob building uses a simple mixture of clay subsoil, aggregate, straw, and water to create solid structural walls, built without shuttering or forms, on a stone plinth. This ancient practice has been used throughout Britain for centuries – in fact, the material is so strong and durable that it is currently in use for forty-five thousand houses in Cornwall, a county in southern England. Building With Cob: A Step-by-step Guide, by Adam Weismann and Katy Bryce, covers everything from design, planning, and siting to roofs, insulation, and floors. It is lavishly illustrated with more than three hundred inspirational color photographs. The authors have recently been commissioned to build a thirty-classroom school in England in 2006; it will be the largest new cob construction project in the Western hemisphere.