Applications and basic principles of absorbers -- Applications and basic priciples of diffusers -- Measurement of absorber properties -- Measurement and characterization of diffuse reflections or scattering -- Porous absorption -- Resonant absorbers -- Some other absorbers -- Prediction of scattering -- Schroeder diffusers -- Geometric reflectors and diffusers -- Hybrid surfaces -- Absorbers and diffusers in rooms and geometric models -- Active absorbers and diffusers