This beginner’s guide is for software developers new to OpenSceneGraph (OSG) who are considering using it in their applications. You need basic knowledge of C++, especially for the standard template library (STL) constructs, which OSG uses extensively, and familiarity with OpenGL, the standard cross-platform low-level 3D graphics API. Some familiarity with design patterns as implemented in C++ is also useful, but not essential. There is some geometry and linear algebra in the book and familiarity with these will be useful too. The book is designed to be placed by the computer as a guide and mentor. It divides the core functionalities of OpenSceneGraph 3D graphics engine into aspects covered in separate chapters, which can be treated as independent units, each covering one important field of OSG programming, along with several examples illustrating concrete usages and solutions. The sequence of chapters is organized from the easy to the more difficult, to help you get to grips with OSG.