The impact of blood viscosity on health and disease has been neglected, even though viscosity is a fundamental property of any fluid. It is inversely proportional to flow, so increased blood viscosity predisposes to thrombosis. Blood viscosity is directly related to systemic vascular resistance, and so blood viscosity affects blood pressure. Blood viscosity is inversely proportional to perfusion, and increased viscosity adversely affects the performance of all organs. By viewing them through the perspective of viscosity, this book provides fresh insight into atherosclerotic cardiovascular disease, hypertension, metabolic syndrome, sepsis, hemolytic anemias, anemia of chronic disease, and aging.