This book introduces students, trainees, and teachers of all school types to the didactic and methodological foundations of geometry teaching in lower secondary education and demonstrates possibilities for problem-oriented lesson design through numerous practical teaching examples. Based on educational standards, it addresses important aspects such as proving and arguing, constructing, problem-solving, as well as learning and teaching concepts. Additionally, it covers the central topics of geometry instruction: shapes and solids, area and volume, symmetry and congruence, similarity and trigonometry. The use of computers is integrated into all chapters, and an overview of the development of central ideas in geometry and geometry teaching concludes the book. This new edition includes current extensions and innovations.