Medicine and engineering work together towards solutions for biomedical problems. The interactions of blood elements with artificial materials (bags, tubes, artificial organs, etc.) require many disciplines for its understanding. Thus the effort presented in this book is the culmination of a genuine discussion on the problems arising in blood banks, in hospitals, in biomaterials development, in experimental hemocompatibility testing when platelets interact with biomaterials. Hematologists, chemists, biologists and engineers have tried to put their own point of view and to understand the point of view of the other disciplines. The main themes that are presented in the discussion are: Platelet collection, storage and transfusion; Hemostasis and