  A review of recent progress in numerical studies of the Anderson transition
in three dimensional systems is presented. From high precision calculations the
critical exponent $\nu$ for the divergence of the localization length is
estimated to be $\nu=1.57\pm 0.02$ for the orthogonal universality class, which
is clearly distinguished from $\nu=1.43\pm 0.03$ for the unitary universality
class. The boundary condition dependences of some quantities at the Anderson
transition are also discussed.
