Scattering Theory for Many Body Quantum Mechanical Systems — : Rigorous Results Spectral decomposition Two space scattering theory Scattering theory for N body systems Exact parametrices Quasibound states and the finiteness of the discrete spectrum Boundary values of the resolvent. General single channel case Boundary values of the resolvent. The general case Non dilation analytic potentials Instability of quasibound state and embedded eigenvalues.