This new and up-to-date book covers the modern geometrical aspects of optics, which is the fundamental level of understanding the technology. Beginning with how light is generated and how fast it travels, the book discusses how materials interact with light, how various materials affect the velocity of light, and the ramifications of change in the speed of light. The concept of the index of refraction, and how it is used with Snell's law to produce image forming systems, is developed. An ideal textbook for advanced undergraduate level courses in geometrical optics, this book will also interest those wanting to learn the concepts and theory of geometrical optics. Each chapter contains worked examples, and there are exercises to reinforce the reader's understanding of material.