This book explores light and other types of waves, using this as a window into other aspects of physics. It emphasizes a conceptual understanding, using examples chosen from everyday life and the natural environment. For example, it explains how hummingbird feathers create shimmering colors, how musical instruments produce sound, and how atoms stick together to form molecules. It provides a unique perspective on physics by emphasizing commonalities among different types of waves, including string waves, water waves, sound waves, light waves, the matter waves of quantum mechanics, and the gravitational waves of general relativity. This book is targeted toward college non-science majors, advanced high school students, and adults who are curious about our physical world. It assumes familiarity with algebra but no further mathematics and is classroom-ready with many worked examples, exercises, exploratory puzzles, and appendices to support students from a variety of backgrounds.