Path of the Pole is a pretty cool Theory involving anthropology, physics, and particularly geology. Charles Hapgood has dedicated his life to this science, My Pop and I had an argument when I was young about whether or not weight on the surface of planet could effect it's rotation. Hapgood makes it perfectly clear that it can influence Planet Earths rotation by weight distribution. He argues that our poles drift, the poles are invisible but can be measured. Illustrations, charts, diagrams, maps, and figures help explain his difficult concepts and makes his theories easy to understand. I recommend this book if you're studying what causes continental drift, shifts in earth's tectonic plates, ice ages to come and go, species to appear on different continents, if you study what causes volcanoes, and most importantly....... what the future of planet earth is. READ IT!