Brand Book
A brand book is a document containing the rules for a brand's visual identity. It specifies the required logo size, which colors and fonts to use, and how to design layouts, documents, emails, and social media posts.
Example: A SaaS service's brand book prohibits changing the color of buttons in partner banners and specifies the clear space around the logo. Communication remains recognizable in both emails and chatbot interfaces, even when the materials are prepared by an external contractor.