Two-boson exchange in electron-nucleon scattering

Electromagnetic two-photon exchange (TPE) corrections were recently found to play an important role in the resolution of the proton electric to magnetic form factor discrepancy between Rosenbluth and polarization transfer experimenmts. I will review the current status of TPE in electron-hadron scattering and present recent applications of the formalism to gamma-Z boson exchange in parity-violating electron scattering. The latter turn out to yield significant corrections to planned measurements of the weak charge of the proton.