Color Glass Condensate and Glasma

We review the color glass condensate effective theory, that describes the gluon content of a high energy hadron or nucleus, in the saturation regime. The emphasis is put on applications to high energy heavy ion collisions. After describing initial state factorization, we discuss the glasma phase, that precedes the formation of an equilibrated quark–gluon plasma. We end this review with a presentation of recent developments in the study of the isotropization and thermalization of the quark–gluon plasma.