  The structure of the near-polar accretion spots on accreting magnetic white
dwarfs has been studied theoretically and observationally in numerous papers
over the last decade. Detailed treatments are available for the regime of low
mass flux, usually termed the bombardment case, and for higher mass fluxes
which create a strong shock standing above the photosphere of the white dwarf.
No general treatment is so far available for the case of shocks buried deep in
the photosphere. I review the theoretical foundations, present some
applications of theory, and discuss in short the open questions which still
need to be addressed.
