Symmetries and hadron form factors

Extended experimental programs on electromagnetic hadron (proton, neutron and meson) form factors are ongoing and planned in space-like and time-like regions. Experimental efforts are devoted to achieve a better precision and/or to access new kinematical regions. Phenomenological work points to an unified description of all existing data. While symmetry properties hold at the level of Born approximation, analyticity connects scattering and annihilation channels and QCD gives predictions for the asymptotic regime. Application to spin 1/2 and spin 1 hadrons are illustrated.