This riveting account of how the poles have often changed position on the earth's surface is the culmination of Hapgood's comprehensive and meticulous research into Antarctica, ancient maps and the geological record. Polar wandering is based on the idea that the outer shell (crust) of the earth shifts about from time to time, moving some continents toward and others away from the poles, changing their climates. Geologists who have accepted that these movements occur generally put the last such change a very long time ago. Hapgood believed that polar wandering was primary and caused the displacement of continents, and that the last shift of the earth's crust took place in recent time, at the close of the last ice age, resulting in major climatic improvements. This is an carefully abridged edition of the original work.