The first volume provides a general overview of the genetics, structure, mechanism and regulation of the Ras superfamily proteins and describes in detail the signaling pathways and processes regulated by specific members of this family. The focus of this first volume is on the Rho and Ras subfamily of small G proteins. The second volume discusses subfamily proteins involved in nucleo-cytoplasmic and vesicular transport mechanisms inside the cell. The focus lies on the Rab, Ran and Arf subfamily members.