MPEJ Volume 4, No.4, 16pp Received: Apr 3, 1998, Revised: Aug 21, 1998, Accepted: Sep 14, 1998 Bernard Helffer, Heinz Siedentop Form Perturbations of the Second Quantized Dirac Field ABSTRACT. We give a criterion on when a form perturbation of the free Dirac operator defines a form perturbation of the second quantized free Dirac field. Moreover, we show that the potentials allowing this quantization are regular in the sense of Klaus and Scharf. Furthermore we prove that only non-local potentials allow for this construction in three dimensions. In two dimensions, though, all local potentials with finite Dirichlet norm are allowed.