This lecture covers the concepts of 3D interaction focusing on selection and manipulation techniques. It discusses methods such as ray-casting, occlusion, and framing for object selection, as well as manipulation through virtual hand control and orientation adjustments. The lecture also explores magic selection techniques like the Go-Go method and the World in Miniature concept. Additionally, it touches upon the benefits and limitations of naturalism in 3D interaction, emphasizing the importance of interaction fidelity and user familiarity.