  We extend the circuit theory of superconductivity to cover transport and
proximity effect in mesoscopic systems that contain unconventional
superconductor junctions. The approach fully accounts for zero-energy Andreev
bound states forming at the surface of unconventional superconductors. As a
simple application, we investigate the transport properties of a diffusive
normal metal in series with a d-wave superconductor junction. We reveal the
competition between the formation of Andreev bound states and proximity effect,
that depends on the crystal orientation of the junction interface.
