The second volume of Arenaviruses deals with the biology and the pathogenesis of arenaviruses primarily through the study of LCMV. The fundamental observation of MHC restriction and CD8 cytotoxic T lymphocyte killing derived initially from studies with LCMV in the mouse, and has been expanded to studies of most human pathogens, viral, bacterial, parasitic, as well as events in cancer. The scope and importance of this observation was recognized by awarding the Nobel Prize in 1996 to Rolf Zinkernagel and Peter Doherty, long-time workers in the field of LCMV and arenavirus biology. Since then, many of the principles for understanding viral pathogenesis and biology of animal viruses have been defined, in great part, from the lessons learned by studying LCMV. Those lessons and their implications are the subject of this second volume on the arenaviruses.