""0. Introduction""; ""1. Metric similarity and entropy""; ""2. Automorphisms of the torus""; ""3. Three kinds of similarity for torus automorphisms""; ""4. Symbolic dynamical systems""; ""5. Main theorem""; ""6. Automorphisms as Markov shifts, cases la and IIa""; ""7. Coding, Case la""; ""8. Coding, Case Ila""; ""9. Representation and coding, Case III""; ""10. Topological entropy""; ""11. Conclusion""; ""Bibliography""