Nonfactorizable Effects in Charmless B Decays and B Meson Lifetimes

Status of nonfactorizable effects in hadronic charmless B decays is reviewed. Implications of new CLEO measurements on $B^0\to\pi^+\pi^-$ and $B\to\eta' K$ are discussed. Nonfactorizable effects due to color ocet 4-quark operators are calculated using renormalization group improved QCD sum rules. The resultant B-meson lifetime ratio $\tau(B^-)/\tau(B_d)$ agrees with experiment.