The influence of the extracorporeal circulation on blood and tissue is still a topic with many question marks. The interaction of foreign surfaces and forces with the living system is often a cause of critical pathologic reactions in the organism which can endanger the success of a perfectly performed cardiac operation. Such results are no longer only a domain of cardiovascular surgery and definitely require the intensive co-operator of many medical and scientific branches. The concept of this book is to link the experiences and observations from the viewpoint of different disciplines and establish a joint field of knowledge in the essentials of the extracorporeal circulation. The contributions contain important information about the effects of blood-material interaction, hematological reactions and clinical aspects.