  The four lectures that I gave in the XIII Ciclo de Cursos Especiais at the
National Observatory of Brazil in Rio in October 2008 were (1) a brief history
of dark matter and structure formation in a LambdaCDM universe; (2) challenges
to LambdaCDM on small scales: satellites, cusps, and disks; (3) data on galaxy
evolution and clustering compared with simulations; and (4) semi-analytic
models. These lectures, themselves summaries of much work by many people, are
summarized here briefly.
