Improved measurement of 2β+γ

We propose to measure the Cabibbo-Kobayashi-Maskawa parameter 2 beta+gamma using B-0 decays involving several intermediate states, and describe a general formalism that applies to a broad class of decays. The main advantage of this method is that the ratios between the interfering amplitudes can be measured without requiring external input. In addition, discrete ambiguities are resolved.