Sepsis evolution and organ dysfunction are still an enigmatic topic. Severe infection causes an important aggression of the whole body, and the so-called inflammation mediators play an important role in this evolution. It is however certain that the immune system is a key factor in sepsis progression. The volume focuses on some primary aspects such as the research of the rationale of the immune system activation during sepsis, on the molecular strategies available for ARDS treatment and on techniques of emofiltration and absorption of endotoxins through apheresis in the septic patient.