1.Symmetry 1.1 Model Surfaces 1.1.1 Surface Versus Bulk 1.1.2 The Surface as a Physical Object 1.2 Two-Dimensional Crystals 1.2.1 Lattice Planes of Bulk Crystals 1.2.2 Oriented Slabs 1.2.3 Ideal Surfaces. Planar Point Groups 1.2.4 Real Surfaces: Reconstruction and Relaxation 1.2.5 Superlattices at Surfaces 1.2.6 Wood Notation 1.2.7 Symmetry Classification 1.3 Reciprocal Space 1.3.1 Direct and Reciprocal Lattices 1.3.2 Brillouin Zones 1.3.3 Projection of 3D Onto 2D Brillouin Zones 1.3.4 Symmetry of Points and Lines in Reciprocal Space 2.Thermodynamics 2.1 Kinetic Processes and Surfaces in Equilibrium 2.2 Thermodynamic Relations for Surfaces 2.2.1 Thermodynamic Potentials 2.2.2 Surface Modification of Thermodynamic Potentials 2.2.3 Surface Tension and Surface Stress 2.3 Equilibrium Shape of Small Crystals 2.3.1 Anisotropy of Surface Energy 2.3.2 Absolute Values for Surface Energies 2.3.3 Wulff Construction 2.4 Surface Energy and Morphology 2.4.1 Facetting and Roughening 2.4.2 3D Versus 2D Growth 2.4.3 Formation of Quantum Dots 2.5 Stoichiometry Dependence 2.5.1 Thermodynamic Approach 2.5.2 Approximations for Surface Energies 2.5.3 Chemical Potentials 2.5.4 Phase Diagrams 2.5.5 Stability of Adsorbates 3.Bonding and Energetics 3.1 Orbitals and Bonding 3.1.1 One-Electron Picture 3.1.2 Tight-Binding Approach 3.1.3 Atomic Orbitals and Their Interaction 3.1.4 Bonding Hybrids 3.1.5 Bonds and Bands 3.2 Dangling Bonds 3.2.1 Formation of Dangling Hybrids 3.2.2 Influence on Electronic States 3.3 Total Energy and Atomic Forces 3.3.1 Basic Approximations 3.3.2 Potential Energy Surface and Forces 3.3.3 Surface Diffusion 3.4 Quantitative Description of Structure and Stability 3.4.1 Density Functional Theory 3.4.2 Band-Structure and Interaction Contributions 3.4.3 Modeling of Surfaces 3.5 Bond Breaking: Accompanying Charge Transfers and Atomic Displacements 3.5.1 Characteristic Changes in Total Energy 3.5.2 Energy Gain Due to Structural and Configurational Changes 3.5.3 Energy Gain and Electron Transfer 4.Reconstruction Elements 4.1 Reconstruction and Bonding 4.1.1 Metallic Bonds 4.1.2 Strong Ionic Bonds 4.1.3 Mixed Covalent and Ionic Bonds 4.1.4 Principles of Semiconductor Surface Reconstruction 4.1.5 Electron Counting Rules 4.2 Chains 4.2.1 Zig-Zag Chains of Cations and Anions 4.2.2 w-bonded Chains 4.2.3 Seiwatz Chains 4.3 Dimers 4.3.1 Symmetric Dimers 4.3.2 Asymmetric Dimers 4.3.3 Heterodimers