Surprises from the search for quark-gluon plasma? When was quark-gluon plasma seen?

Abstract

The historical context of the recent results from high energy heavy ion reactions devoted to the search of quark-gluon plasma (QGP) is reviewed, with emphasis on the surprises encountered. The evidence for QGP from heavy ion reactions is compared with that available from particle reactions.

Comments: 43 pages, 8 figures, Corrected typos and minor stylistic changes