Terrestrial arthropods (insects, spiders, etc.) dominate the world in numbers and extreme diversity. This book presents the combined views of a physicist, a chemist, and a biologist on the fascinating interactions of these organisms with the primary source of energy on Earth, light. It describes the plethora of important phenomena observed in different spectral ranges, from ultraviolet to visible to mid-infrared. These phenomena, often unprecedented, occur at all scales - macroscopic, microscopic, and nanoscopic. They are richly illustrated with original and aesthetic high-quality images. The descriptions and explanations are comprehensive for researchers and students as well as entomologists and, in general, accessible to anyone fascinated by the beauty and complexity of nature. More detailed explanations are presented in appendices for ease of reading. They may be omitted without affecting the general understanding of the main text. Researchers and engineers will also find numerous avenues for bioinspired developments in various fields such as energy, environment, agriculture, and ecology.