Blood coagulation and fibrinolysis has been traditionally classed as a part of hematology and the complement system as a part of immunology. An analysis of these two systems at a molecular level, however, has revealed some intriguing evolutionary relationships among some of the macromolecules involved. Evidently, there are similarities in the cascade of reactions that characterize the processes. It is therefore highly suitable that these topics are presented together in one volume. This book presents a thorough explanation and analysis of our current understanding of the proteins and enzymes involved in each of the three processes, and includes a section devoted to special topics of relevance, such as the kinin system, glycosylation, signal peptides, and the serpin family.