This chapter begins with the story of the attempts made over the centuries to infuse blood from one individual to another. Only during the Spanish Civil War were the attempts of transfusing blood made by Norman Bethune and Federico Duran Jorda successful. Their experience was very important for the blood transfusion program set up during the Second World War (WWII), but preliminary attempts were based on the use of whole blood of group ‘O’. It was after WWII, that transfusion programs began to function everywhere in Europe and only later Charles Drew and Edwin Cohn understood that blood and plasma could be ‘fractionated’ into different components with techniques that allowed blood fractions to be used for different medical conditions and permitting its storage for periods depending on the nature of the fraction and the temperature.