Book excerpt: About the way we use and reuse the resources in the building industry and ultimately eliminate the concept of waste. The book seeks to provide inspiration for 'building a circular future' by providing a set of principles and bringing forward the best practices from in and outside the building industry. This book presents findings, case studies, background and context for the project ?Building a Circular Future?, and consist of three main chapters: Design for Disassembly, Material Passport and Circular Economy. All content comes from extensive research and through workshops with partners across industries. The book furthermore provides 15 principles for "Building a Circular Future" and a thoroughly calculated business case, which documents that a demolition, that today would cost ?2.151.249,56 can be turned into a ?4.705.858,41 business upside in a future circular building industry.