This is a comprehensive overview of the information yieldedby electroweak probes about the nuclear- andsubnuclear-scale structure of matter. Lepton-inducedprocesses from low energy through to the highest energiesare considered. The first three lectures reviewelectromagneticprocesses in hadrons; others cover theproperties of partons, the behaviour of the constituents ofthe hadron, muon and neutrino scattering etc. Anintroduction to electroweak theory including the status ofprecision tests and data analyses is given along with areport on the first results from HERA.The lecturers have endeavoured to achieve a balance betweenscientific and didactic aspects thus making the bookaccessible also to students of nuclear and particle physics.