  The role of penguin amplitudes in CP violating $B$ decays is reviewed,
emphasizing recent progress in the analysis of electroweak penguin
contributions. It is shown how these terms are included in a model-independent
manner when measuring the weak phase $\alpha$ in $B\to\pi\pi$ using isospin
symmetry, and when determining the phase $\gamma$ from $B\to K\pi$ applying
flavor SU(3). Uncertainties due to rescattering effects in $B\to K\pi$ are
discussed.
