The Planet Earth, Second Edition focuses on the advances in geophysical sciences and fundamental laws of nature. This edition introduces a new chapter (Chapter 17), which discusses Van Allen radiation belts. The rest of the chapters have also been modified and updated with additions on the work and achievements of the International Geophysical Year (IGY); Mohole project; continental drift and polar wandering; exosphere; state of the theory of magnetic storms and aurorae; and possibility of extra-terrestrial sources of life. Topics also deliberated in this book include origin, age, and possible ultimate fate of the earth; general circulation of the atmosphere and oceans; aurorae and magnetic storms; and genesis of life. This publication is a good reference for students and researchers conducting work on geophysics.