Book excerpt: This book is based on a course given by the author to third and fourth year undergraduate students from physics, engineering physics and electrical engineering. The purpose is to introduce and explain some of the fundamental principles underlying laser beam control in optoelectronics, especially those in relation to optical anisotropy which is at the heart of many optical devices. The contents of the book are scattered in many sources and there seems to be no single source available at the undergraduate level. That is why the present book is written. The book attempts to give the reader a good background needed for working in a laser, optoelectronic or photonic laboratory so that the use of equipment and the control of laser beams can be mastered without difficulty.