To understand the circular value potential of materials, products and systems, one requires a reliable set of information. Materials Passports aim to provide this information. This paper explores the need for passports as well as their goals and functions. The types of information a Materials Passports should be able to contain are discussed, and how they relate to existing tools in the marketplace. The focus of Materials Passports on putting the Circular Economy into practice by value creation through recovery and how this encourages innovation is described.