Innate Immunity has long been regarded as the non-specific arm of immune response, acting immediately and in a generic way to defend the host from infections. In the post genomic era, our knowledge of the innate immune system is enriched by findings on the specificity of innate immune reactions as well as to novel functions that do not strictly correlate with immunological defense and surveillance, immune modulation or inflammation. The advent of high-throughput platforms for genome and proteome-wide profiling, together with the enormous quantity of raw genetic information that has accumulated in the databases, have stirred new expectations in biomedical research, and led scientists to revisit established biological systems from a global and integrative perspective. Innate Immunity research now faces the challenge of integrating isolated biochemical pathways into complex gene and protein regulatory circuits. This volume collects topics on natural killer cells, mast cells, phagocytes, toll-like receptors, complement, host defense in plants and invertebrates, evasion strategies of microorganisms, pathophysiology, protein structures, design of therapeutics, and experimental approaches discussed during the conference.