Towards a Theory of Charmless Non-Leptonic Two-Body B Decays

We address a number of theoretical and phenomenological issues in two-body charmless non-leptonic B decays in the context of a factorization model. A classification of the exclusive decays involving tree and penguin amplitudes is reviewed. The role of QCD anomaly in exclusive decays involving an $\eta$ or $\eta'$ is elucidated and comparison is made with the existing data. We argue that the factorization approach accounts for most of the observed two-body B decays.