This is a review monograph on quark-gluon plasma (QGP). Different theoretical and experimental aspects of the program to produce QGP in relativistic heavy-ion collisions are covered by experts in the field. This is the third volume in a series on the subject, and the first such monograph to focus on the implications of the experimental results from RHIC, the relativistic heavy-ion collider at the National Brookhaven Laboratory. The review articles will be useful to experienced researchers as well as to graduate students entering the field.