The CQM model
I review a Constituent-Quark-Meson model (CQM) for heavy meson decays, outlining its characteristics and the calculation techniques developed for it. The strength of this effective model is that it enables to evaluate heavy meson decay amplitudes through diagrams where the heavy mesons are attached at the ends of loops containing heavy and light quark internal lines. The phenomenological applications are presented in detail, trying to give a self-contained operative picture of the model.