1.Introduction. 2.Examples. 3.Recurrence. 4.Mean convergence. 5.Pointwise convergence. 6.Comments on the ergodic theorem. 7.Ergodicity. 8.Consequences of ergodicity. 9.Mixing. 10.Measure algebras. 11.Discrete spectrum. 12.Automorphisms of compact groups. 13.Generalized proper values. 14.Weak topology. 15.Weak approximation. 16.Uniform approximation 17.Category. 18.Invariant measures. 19.Invariant measures: the solution. 20.Invariant measures: the problems. 21.Generalized ergodic theorems. 22.Unsolved problems. 23.Reference.