Book excerpt: What Is Lighting Design?: A Genealogy of People and Ideas explains what lighting design is by looking at the history of ideas that are a part of this craft and how those ideas developed. Lighting design began in the West with the Renaissance, and each historical period since then has modified how and why light is used in performance, the methods for producing light, and the consensus around what its purpose is. Exploring each lighting design era and the basic components of lighting design, the book discusses how the central ideas of this craft developed over the past 500 years, what today’s lighting designers are concerned with, and how lighting design contributes to performances. This book is designed as a main course text for History of Lighting Design university courses and a supplementary text for and Introduction to Lighting Design, Stagecraft, and Scenography courses. It will also be of interest to directors, choreographers, and working lighting designers who wish to explore the history and meaning of their craft.