The text consists in three parts. The first part develops a theory of period mappings of Hodge-de Rham type for families of complex manifolds, the essential argument being that the manifolds in question need neither be compact nor Kahler. For compact Kahler manifolds we fall back onGriffiths classical theory of period mappings. The second part investigates the degeneration behavior of the relative Frolicher spectral sequence associated to a submersive morphism of complex manifolds, the main point again being that the fibers of the morphism in question need neither be compact nor Kahler. In...