The study of the phase structure of strongly interacting matter under extreme conditions of
temperature and density addresses fundamental aspects of QCD, among them the
mechanism of confinement, the origin of the spontaneous breaking of chiral symmetry and
their importance for the generation of mass. Dileptons emitted in collisions of heavy ions offer
the unique opportunity to investigate the microscopic properties of strongly interacting matter
under such extreme conditions. This contribution discusses important experimental results in
dilepton spectroscopy obtained so far by HADES. It will also address the tong-term goal of
this research at GSI/FAIR, i.e. the establishment of a complete excitation function of dilepton
production from energies of 1A GeV up to 11A GeV with HADES and CBM.
