On irreducibility of the principal series.- La Formule de Plancherel Pour un Groupe de Lie Resoluble Connexe.- On finite generation of invariants for certain sub-algebras of a semi-simple lie algebra.- Generic representations.- A characteristic variety for the primitive spectrum of a semisimple lie algebra.- Remarque sur la Covariance de Certains Operateurs Differentiels.- Classification theorems for representations of semisimple lie groups.- Integrales d'Entrelacement sur des Groupes de Lie Nilpotents et Indices de Maslov.- Decomposition Spectrale des Repr¿ntations Lisses.- Two character identities for semisimple lie groups.- Spherical functions in spin0(1, d)/Spin(d?1) for d=2, 4 and 8.