This book is devoted to the wooden mineheads of the eastern regions of Pennsylvania. When many mines were forced to close during the Great Depression, jobless miners built clandestine mines in the wooded Appalachian foothills. In the valleys large investments were needed to mine the anthracite coal from deep shafts. In the hills, it was possible to access smaller coal deposits directly from the surface inexpensively. Wooden mineheads, or "tipples," pulled coal cars out of the mining tunnels to the surface. The angle of the coal bed and the slope of the surface determined the shape of the tipple. These pre-industrial-looking structures of varying shapes and heights were built by companies of usually three to five men. Wood was used to save costs. Some are still in operation today and remain the last traces of an extraction method that was used all over the world before mineheads were built of steel. Bernd and Hilla Becher photographed the Pennsylvania Coal Mine Tipples in 1974–75 and 1977–78.