Book excerpt: Looking Into the Earth comprehensively describes the principles and applications of both 'global' and 'exploration' geophysics. Mathematical and physical principles are introduced at an elementary level, and then developed as necessary. Student questions and exercises are included at the end of each chapter. The book is aimed primarily at introductory and intermediate university (and college) students taking courses in geology, earth science, environmental science, and engineering. It will also form an excellent introductory textbook in geophysics departments, and will help practising geologists, archaeologists and engineers understand geophysical principles.