Thermodynamics of Adsorption--Localized Adsorption - Independent Systems--Localized Adsorption - Dependent Systems--Nonlocalized Adsorption--Physical Forces of Adsorption--The Chemical Forces of Adsorption - Metal--The Chemical Forces of Adsorption - Semiconductors--The Kinetics of Chemisorption--Adsorption and Catalysis--Kinetics of Heterogeneous Catalysis - Diffusion Steps Neglected--Kinetics of Heterogeneous Catalysis - Diffusion Controlling--Geometric Factors and Catalysis--Electronic Factors in Catalysis - Metals--Electronic Factors in Catalysis - Semiconductors--The Nature of Surface Species and Their Role in Catalysis