Abstract
We formulate a novel relativistic Faddeev theory of the πNN system using a variable-mass isobar ansatz for the πN and NN amplitudes and the requirement that the spectator particles be always on their mass shells. This theory takes into account the two possible time orderings in the propagator of the exchange particle and describes correctly the coupling between the two-body and three-body channels. As a first application of this theory, we study pion-deuteron elastic scattering by calculating all the observables in the region of the 3,3 resonance for which data exist.