The aim of this volume is to enable those who are interested in Stonehenge and other great stone monuments of England to learn something of the similar buildings which exist in different parts of the world, of the men who constructed them, and of the great archæological system of which they form a part. It is hoped that to the archæologist it may be useful as a complete though brief sketch of our present knowledge of the megalithic monuments, and as a short treatment of the problems which arise in connection with them.