  We provide an up to date account of progress in understanding the origin of
the observed baryon asymmetry of the universe. While our primary goal is to be
current, we have attempted to give a pedagogical introduction to the primary
areas of research in this field, giving a detailed description of the different
scenarios. The very recent developments in GUT baryogenesis, leptogenesis,
electroweak baryogenesis and the Affleck-Dine mechanism are presented. In
particular, we focus on specific particle physics implementations, mostly in
the context of supersymmetry, which lead to specific testable predictions.
