The Schrodinger equation -- The particle in a box -- Operators -- The harmonic oscillator -- Angular momentum -- The hydrogen atom -- Theorems of quantum mechanics -- The variation method -- Perturbation theory -- Electron spin and the spin-statistics theorem -- Many-electron atoms -- Molecular symmetry -- Electronic structure of diatomic molecules -- Theorems of molecular quantum mechanics -- Molecular electronic structure -- Electron-correlation methods -- Semiempirical and molecular-mechanics treatments of molecules -- Comparisons of methods.