New forms of QCD matter discovered at RHIC

We discuss two special limiting forms of QCD matter which may be produced at RHIC. We conclude from the available empirical evidence that an equilibrated, but strongly coupled quark-gluon plasma has been made in such collisions. We also discuss the growing body of evidence that its source is a color glass condensate. (c) 2004 Elsevier B.V. All rights reserved.