Principles of Quantum Theory and of the Theory of the Chemical Bond. Basic Quantum Mechanics: the Schroedinger Equation and Its Solutions for a Rotator in the Plane. the Harmonic Oscillator. the Hydrogen Atom. Quantum Mechanical Operators. the Variation Principle. Perturbation Theory. Spin. the Helium Atom. the Pauli Principle. Many Electron Atoms. the Hartree- Fock Method. the Structure of the Periodic Table. Simple Diatomic Molecules: the Valence-Bond Method, the Method of Molecular Orbitals, Hetero-Atomic Molecules. Polyatomic Molecules: Localized Molecular Orbitals, Hybridization, Conjugated and Aromatic Molecules. Time-Dependent Perturbation Theory: Transition Probabilities, the Franck-Condon Principle.