This is a historical book. When the first settlers landed on American shores, the difficulties in finding or making shelter must have seemed ironical as well as almost unbearable. The colonists found a land magnificent with forest trees of every size and variety, but they had no sawmills, and few saws to cut boards; there was plenty of clay and ample limestone on every side, yet they could have no brick and no mortar; grand boulders of granite and rock were everywhere, yet there was not a single facility for cutting, drawing, or using stone. These homeless men, so sorely in need of immediate shelter, were baffled by pioneer conditions, and had to turn to many poor expedients, and be satisfied with rude covering. In Pennsylvania, New York, Massachusetts, and, possibly, other states, some reverted to an ancient form of shelter: they became cave-dwellers.