  I review, some of the algebraic and geometric structures that underlie the
theory of Special Relativity. This includes a discussion of relativity as a
symmetry principle, derivations of the Lorentz group, its composition law, its
Lie algebra, comparison with the Galilei group, Einstein synchronization, the
lattice of causally and chronologically complete regions in Minkowski space,
rigid motion (the Noether-Herglotz theorem), and the geometry of rotating
reference frames. Representation-theoretic aspects of the Lorentz group are not
included. A series of appendices present some related mathematical material.
