Virtual Compton scattering at low energy and the generalized polarizabilities of the nucleon

Virtual Compton scattering on the nucleon: γ∗N→γN is a new and rapidly developing field at low and high energies, with the emergence of recent concepts such as generalized parton distributions at high energy, and Generalized Polarizabilities (GPs) at low energy. This lecture is about the low energy part, i.e. for energies in the (γp) center-of-mass mainly up to the Δ(1232) resonance region. I review the concept of GPs and the experiments dedicated to their measurement.