Maps are pervasive in our world: so indispensable, and so disposable that thousands are made, used, and discarded every day. Yet not long ago, maps were both rare and strange technological things. When and why did modern mapping systems come into being? Behind this transformation lie contentious stories of objects and people, makers and users, global forces and local dynamics, metropoles and colonies, and technologies and cultures. Focusing on the modern period, each week illuminates maps and their importance in our world by focusing on a keyword, such as power, territory, worldmaking, boundaries, imperialism, capitalism, literacy, verticality, and countermapping.