Collective Fields for QCD

A gauge-symmetric approach to effective Lagrangians is described with special emphasis on derivations of effective low-energy Lagrangians from QCD. The examples we discuss are based on exact rewritings of cut-off QCD in terms of new collective degrees of freedom. These cut-off Lagrangians are thus effective'' in the sense that they explicitly contain some of the physical long-distance degrees of freedom from the outset.(Talk presented by P.H. Damgaard at the workshop on Quantum Field Theoretical Methods in High Energy Physics’', Kyffhauser, Germany, Sept. 1993. To appear in those proceedings).