We construct a new class of representations of the canonicalcommutation relations, which generalizes previously known classes. Weperturb the infinitesimal generator of the initial Fock representation (in other words, the free quantum field) by a function of the field which issquare-integrable with respect to the associated Gaussian measure. Wecharacterize perturbations which lead to representations of the canonicalcommutation relations. We provide conditions entailing the irreducibility of such representations, show explicitly that our class of representations subsumes previously studied classes, and give necessary and sufficient conditions for our representations to be unitarily equivalent, or just quasi-equivalent, with Fock, coherent or quasifree representations. 1991 Mathematics Subject Classification: 81S05, 46L60, 81T05.