Includes bibliographical references and indexes.

Basic phenomenology -- Scales -- Observational windows -- Classifications -- Photometry, kinematics, and dark matter -- Basic questions, semiempirical approach, and the dynamical window -- Physical models -- Self-gravity and relation to plasma physics -- Relaxation times, absense of thermodynamical equilibrium -- Models -- Equilibrium and stability : symmetry and symmetry breaking -- Classical ellipsoids -- Introduction to dispersive waves -- Jeans instability -- Spiral galaxies -- Orbits -- The basic state : vertical and horizontal equilibrium of the disk -- Density waves -- Roles of gas -- Global spiral modes -- Spiral structure in galaxies -- Bending waves -- Dark matter in spiral galaxies -- Elliptical galaxies -- Orbits -- Stellar dynamical models -- Stability -- Dark matter in elliptical galaxies -- In perspective -- Selected aspects of formation and evolution -- Galaxies and gravitational lensing -- Self-gravitating accretion disks.