  Using an approach based on quasiclassical Green's functions we present a
theoretical study of transport in mesoscopic S/N structures in the diffusive
limit. The subgap conductance in S/N structures with barriers (zero bias and
finite bias anomalies) are discused. We also analyse the temperature dependence
of the conductance variation $\delta S(T)$ for a Andreev interferometer. We
show that besides the well know low temperature maximum a second maximum near
$T_c$ may appear. We present the results of studies on the Josephson effect in
4 terminal S/N/S contacts and on the possible sign reversal of the Josephson
critical current.
