Physics of Event Generators
  An event generator for nuclear collisions is a microscopic model, obtained from extrapolating elementary interactions -- as electron-positron annihilation, deep inelastic scattering, and proton-proton interactions -- towards proton-nucleus and nucleus-nucleus scattering, by using Monte Carlo techniques.   In this paper, we will discuss the physical concepts behind such event generators. We first present some qualitative discussion of nuclear scattering, before discussing particle production and strings. We then discuss the parton model, and finally multiple scattering theory. 
K. Werner