E. Skibsted Spectral analysis of N-body systems coupled to a bosonic field (4546K, postscript) ABSTRACT. We develop an extension of the abstract Mourre theory which consecutively is used to prove spectral properties of various systems coupled to a massless bosonic field. Our models include the spin--boson model and the standard model of quantum electrodynamics for a non--relativistic atom considered recently in [HS] and [BFS], respectively.