Penguins in CP violating B decays

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.