1 Quantum Wells and Superlattices -- 2 Crystal Symmetry -- 2.1 Symmetry Operations, Groups -- 2.2 Point-Group Classification -- 2.3 Space Groups -- 2.4 Group Representations, Characters -- 2.5 Point-Group Representations -- 2.6 Spinor Representations -- 2.7 Representations of Space Groups -- 2.8 Invariance Under Time Inversion -- 2.9 Selection Rules -- 2.10 Determination of Linearly Independent Components of Material Tensors -- 3 Electron Spectrum in Crystals, Quantum Wells and Superlattices -- 3.1 The k-p Method -- 3.2 The Effective-Mass Method; Deformation Potential -- 3.3 Method of Invariants -- 3.4 Electron and Hole Spectrum in Diamond- and Zincblende-Type Cubic Crystals -- 3.5 Electron Spectra of Quantum Wells and Superlattices -- 3.6 Hole Spectrum in Quantum Wells and Superlattices for Degenerate Bands -- 3.7 Deformed and Strained Superlattices -- 3.8 Quantum Wells and Superlattices in a Magnetic Field -- 3.9 Spectrum of Quantum Wells and Superlattices in an Electric Field -- 4 Vibrational Spectra of Crystals and Superlattices Electron-Phonon Interaction -- 4.1 Normal Vibrations: Distribution in Irreducible Representations -- 4.2 Vibrational Spectra of Superlattices -- 4.3 Electron-Phonon Interaction -- 5 Localized Electron States and Excitons in Heterostructures -- 5.1 Shallow Impurity Centers -- 5.2 Localized States at Superlattice Defects -- 5.3 Excitons -- 5.4 Exchange Splitting of Exciton Levels -- 6 Interband Optical Transitions -- 6.1 Optical Superlattices -- 6.2 Interband Transitions and Dielectric Susceptibility of a Periodic Heterostructure -- 6.3 Coulomb Interaction Between the Electron and the Hole -- 6.4 Exciton Polaritons in an Optical Superlattice -- 6.5 Light Reflection -- 6.6 Electro-Optical Effects in Interband Transitions -- 6.7 Magneto-Optical Spectra -- 7 Intraband Transitions -- 7.1 Cyclotron Resonance and Effective Electron Mass -- 7.2 Intersubband Absorption -- 7.3 Electron-Spin Resonance -- 7.4 IR Reflection in an Undoped Superlattice -- 8 Light Scattering -- 8.1 Theory of Light Scattering in Semiconductors -- 8.2 Scattering by Intersubband Excitations -- 8.3 Scattering by Acoustical Phonons with a Folded Dispersion Law -- 8.4 Scattering by Optical Phonons in Heterostructures -- 8.5 Acceptor Spin-Flip Raman Scattering -- 9 Polarized Luminescence in Quantum Wells and Superlattices -- 9.1 Luminescence as a Tool to Study Electronic Spectra and Kinetic Processes in Two-Dimensional Systems -- 9.2 Luminescence in the Quantum Hall Regime, Quantum Beats -- 9.3 Optical Spin Orientation and Alignment of Electron Momenta -- 9.4 Optical Orientation and Alignment of Excitons -- 9.5 Polarized Luminescence of Excitons and Impurities in an External Magnetic Field -- 10 Nonlinear Optics -- 10.1 Two-Photon Absorption -- 10.2 Photoreflectance -- 10.3 Diffraction from a Light-Induced Spatial Grating -- 10.4 Third-Harmonic Generation -- 10.5 Linear and Circular Photogalvanic (Photovoltaic) Effects -- 10.6 Current of Optically Oriented Electrons -- 10.7 Photon Drag Current -- References.