B Decays - Measurements and Predictions

Hadronic decays of $B$ mesons are reviewed. First, masses of $B$ mesons and observed patterns together with physics behind them are discussed. Then the effective Hamiltonian responsible for major decays is presented and its practical applications are discussed in the context of factorization. Various tests of factorization are then studied. For rare decays, the focus is placed on $K\pi$, $\pi\pi$ final state and the penguin-mediated $X_s\gamma$. In general, the measurements are in excellent agreement with predictions of the standard model.