"The Black Prism" is the first book in the Lightbringer series by author Brent Weeks. It follows the story of Gavin Guile, the world's most powerful person known as the Prism, who can manipulate light and color to create magic. The narrative explores themes of power, identity, and sacrifice as Gavin faces challenges from both external enemies and his own past. The world of "The Black Prism" is divided into different nations, each with its own unique culture and magic system based on the manipulation of light. The story introduces various characters, including Karris White, who becomes pivotal in the unfolding events, as they navigate political intrigue and personal struggles in a richly developed fantasy setting.