Fiber-optic communication systems have advanced dramatically over the last four decades, since the era of copper cables, resulting in low-cost and high-bandwidth transmission. Fiber optics is now the backbone of the internet and long-distance telecommunication. Without it we would not enjoy the benefits of high-speed internet, or low-rate international telephone calls. This book introduces the basic concepts of fiber-optic communication in a pedagogical way. The important mathematical results are derived by first principles rather than citing research articles. In addition, physical interpretations and real-world analogies are provided to help students grasp the fundamental concepts. Key Features: Lucid explanation of key topics such as fibers, lasers, and photodetectors. Includes recent developments such as coherent communication and digital signal processing. Comprehensive treatment of fiber nonlinear transmission. Worked examples, exercises, and answers. Accompanying website with PowerPoint slides and numerical experiments in MATLAB. Intended primarily for senior undergraduates and graduates studying fiber-optic communications, the book is also suitable as a professional resource for researchers working in the field of fiber-optic communications.