  In this review article we briefly summarize the main experimental properties
of (III,Mn)V ferromagnets and outline several different but related approaches
that have been explored in an effort to gain insight into these materials. The
main body of the paper deals with the development of the semi-phenomenological
model in which the low energy degrees of freedom are exchange-coupled
valence-band holes and $S=5/2$ Mn local moments. We discuss physical
predictions based on a mean-field treatment of the disorder-free model and
demonstrate that it successfully describes a number of non-trivial properties
of (Ga,Mn)As and (In,Mn)As ferromagnets. Study of collective excitations of
these ferromagnets shows that the simple mean-field-theory is reasonably
reliable for typical parameters of current samples but must fail at large
carrier densities and also in the limit of very strong exchange coupling.
Finally we discuss the results of Monte Carlo calculations that describe the
effect of collective fluctuations of Mn moment orientations. The method can
deal with some of the complications and additional physics, including the
possibility of non-collinear ground states, that enters when disorder is added
to the theoretical model.
