  A reformulation of quantum mechanics called ``hybrid interaction picture''
(HIP) is proposed. In contrast to its current non-Hermitian-interaction-picture
(NIP) predecessor the new formalism combines a simplification of the NIP
Hilbert-space metric with an innovative preconditioning of the observables of
interest. Via an illustrative example it is shown that the idea might open new
ways towards optimal model-building strategies in quantum theory of unitary
systems.
