The fourth edition of Pedrottis' Introduction to Optics is a comprehensive revision of a classic guide to the fascinating properties of light, now with new authors. Ideally suited for undergraduate optics courses in physics and electrical/electronic engineering departments, this edition adopts a distinctive phenomenological approach, bringing the underlying science to life through interactive simulations and beautifully revised figures. The modular structure and succinct style of previous editions has been maintained, while the content has been modernized, new topics have been added, and a greater consistency of terminology attained. For even more effective learning, a recurring theme of student engagement runs throughout the text, supported by a multifaceted pedagogical package that reinforces key concepts, develops a clear understanding of optical technologies and applications, and connects to students' experiences and observations from everyday life.