  Heavy Quark Effective Theory (HQET) is a new approach to QCD problems
involving a heavy quark. In the leading approximation, the heavy quark is
considered as a static source of the gluon field; 1/m corrections can be
systematically included in the perturbation theory. New symmetry properties not
apparent in QCD appear in HQET. They are used, in particular, to obtain
relations among heavy hadron form factors. HQET also simplifies lattice
simulation and sum rules analysis of heavy hadrons.
