Strangeness production in ultra relativistic heavy-ion collisions

The interest in strange particle production in heavy-ion collisions stems from the prediction, originally made in 1980-82, that the onset of a quark-gluon plasma phase during the interaction would lead to equilibration of strange quarks on a time scale of a few fm/c, and to the formation of multi-strange baryons and antibaryons close to thermal and chemical hadronic equilibrium. The experimental situation will be reviewed with particular emphasis on the recent results obtained in Pb-Pb collisions at the CERN SPS. Strange particle evidence for the onset of a plasma phase during such collisions will be presented. (24 refs).