OpenSCAD is a free open source software for the creation of three-dimensional geometries. In contrast to common CAD systems such as Fusion 360 or SolidWorks, geometries in OpenSCAD are defined by a purely textual description. This means that all elements of a geometry are inherently parameterized and can be easily adapted. This high flexibility makes OpenSCAD particularly suitable for the design of technical systems and and their components, for example in the context of 3D printing. The book Mastering OpenSCAD introduces you to all important concepts and functionalities of OpenSCAD. The book guides you through 10 selected projects step by step, each project focusing on a limited set of functions and concepts. After these 10 projects, you will know all practically relevant features of OpenSCAD. For the sake of completeness, a final chapter briefly presents the functions that were not addressed in any of the projects.