Opening Remarks.- I The Structure of Surfaces.- Calculation of Surface Structural Energies.- A New Model for the Cleaved Si (111)-(2xl) Surface.- Diffuse LEED, Tensor LEED, and the Structure of Random Adsorbates.- Surface Structure Study by High-Resolution Electron Microscopy and Diffraction.- Complete Surface Structures.- General Discussion.- II Surface Science and Catalysis.- The Activation of Chemical Bonds at Surfaces.- Collision Induced Dissociation and Desorption: CH4 on Ni(111).- Associated Effect in Adsorbed Layer.- The Surface Chemical Bond of Adsorbed Organic Monolayers and Adsorbate-Induced Restructuring of Surfaces.- The Atomic Structure of the Liquid-Vapor Interface of a Metal: An Example of the Influence of Strong Density Dependence of the Interatomic Potential.- Discussion on Observation of Phase Transition and Adsorption Processes in Real Space (16 mm movie).- III Two-Dimensional Physics/Phase Transitions.- Phase Transitions at Interfaces: Roughening, Surface Melting, and Triple Point Wetting.- Theory of Surface Melting and Non-Melting.- Is a Liquid Supported Amphiphile Monolayer Aptly Described as a Two-Dimensional System?.- Measurement of Non-Equilibrium Diffusion from Two-Dimensional Ordering Kinetics.- Metastable Magnetic Epitaxial Thin Films.- General Discussion.- IV Scanning Tunneling Microscopy.- Tunneling Microscopy.- Theory of Single-Atom Imaging in the Scanning Tunnelling Microscope.- Electronic Processes at Disordered Surfaces.- Recent Results in Scanning Tunneling Microscopy.- Preliminary Studies on the Interface Structures of CaF2/Si(111).- Spectroscopic Imaging of Surfaces with Atomic Resolution.- General Discussion.- V Surface Scattering and Surface Dynamics.- The Study of the Forces Between Atoms of Single Crystal Surfaces from Experimental Phonon Dispersion Curves.- Self-Consistent Theory of Surface Phonon Dispersion Curves at the (110) Surface of Aluminum.- Carrier Excitation Yield from Atomic Collisions at Semiconductor Surfaces.- Simulation Studies of Structure and Vibrations of Clean Transition Metal (001) Surfaces Across the Reconstruction Phase Transition.- Soluble Models in Surface Collision Dynamics.- General Discussion.- VI Chemical Reactions at Surfaces.- Dynamics of Chemical Interactions at Surfaces.- The Photochemistry of Methyl Halides Adsorbed on Pt(111).- Hydrogen Spillover on Oxide Surfaces.- The Sticking of Ne on Ru(001): Quantum vs. Classical Behavior.- Atomic and Electronic Structure of Compound Semiconductor Interfaces.- General Discussion.- VII Solid-Solid Interfaces and Superlattices.- Solid-Solid Interfaces and Superlattices.- Electronic Structures of Strained Layer Superlattices (Si)m/(Si1-xGex)m(100) with m=1 and m=2n (n=1-10).- First-Principles Calculations of Quasiparticle Energies at Surfaces and Interfaces: Semiconductor Surface-State Spectra and Band Offsets.- Comparison of Interfacial Charge Densities, Valence Band Offsets, and Formation Enthalpies of (GaAs)n(AlAs)n(001), (110), and (111).- Surface Segregation at Metal/m-V Compound Semiconductor Interfaces.- General Discussion.- VIII Surface Studies with Synchrotron Radiation.- Dynamical Response of a Metal Surface.- Advances in Surface Crystallography by Multishell SEXAFS.- Chemical Effects in Surface-Enhanced Raman Scattering.- Magneto-Optic Kerr Effect Studies of Two-Dimensional Magnetism.- Surface vs. Bulk Hysteresis Loops.- Near Edge X-Ray Absorption Fine Structure (NEXAFS) of Molecules Adsorbed on Surfaces.- High Resolution Core Level Shift Spectroscopy from Tungsten Single Crystal Planes.- Surface Spectroscopy of High-Tc Y-Ba-Cu-O Superconductors.- Administrative Council and Scientific Committees of the Solvay Foundation.- Organizing Committee of the Solvay Conference.- List of Participants.- Index of Contributors.