  The current status of evaluating thermal production of lepton pairs in
high-energy collisions of heavy nuclei is discussed. After a brief survey of
emission rates from hot and dense matter, we address applications to (and
interpretations of) recent SPS data including 40 AGeV CERES results, as well as
prospects for NA60. Emphasis is put on predictions for RHIC. In particular,
implications of hadronic observables and first single-electron measurements at
$\sqrt{s}=130$ AGeV for upcoming pair spectra from PHENIX at $\sqrt{s}=200$
AGeV are assessed.
