  We derive the $\sigma$-model for granular metals. It is valid for any
relation between the temperature, $T$, and the grain mean level spacing. The
continuum limit of the $\sigma$-model describes non-perturbative charging
effects in homogeneous disordered metals. The $\sigma$-model action contains a
novel term which is crucial for studying Coulomb blockade effects. Topological
properties of the $\sigma$-model encoding charge discreteness are studied. For
$T$ below the escape rate from the grain, $\Gamma$, Coulomb blockade effects
are described by solitons of the $Q$-matrix which are delocalized in real
space. At $T> \Gamma $ the solitons transform into phase instantons localized
at a single tunneling contact.
