This lecture provides an introduction to the mastery of land in Swiss law, focusing on the distinctions between public and private law. It begins with the fundamental concepts of state, space, and property, emphasizing the legal frameworks governing land use. The instructor discusses the logic of decisions made by authorities, highlighting how administrative decisions impact individual rights and obligations. The lecture also covers the importance of public law in regulating land use, including the necessity of obtaining permits for construction and the implications of environmental protection laws. Furthermore, the discussion extends to the rights of individuals regarding property, including the distinction between public and private spaces. The instructor elaborates on the legal definitions of persons and things, the capacity of individuals to hold rights, and the protection of personal rights against third parties. The session concludes with an overview of contractual obligations in the context of land use, particularly in public procurement processes, illustrating the interplay between public and private law in land management.