Higgs boson production in e^+e^- and e^-e^- collisions

When Higgs boson candidates will be found at future colliders, it becomes imperative to determine their properties, beyond the mass, production cross section and decay rates. Other crucial properties are those related to the behaviour under CP transformations, and the self-couplings. This paper addresses the question of measurability of some of the trilinear couplings of MSSM neutral Higgs bosons at a high-energy e^+e^- collider, and the possibilities of exploring the Higgs boson CP properties at e^+e^- and e^-e^- colliders.