The book examines recent methods used for blood flow modeling and associated in vivo experiments, conducted using experimental data from medical imaging. Different strategies are proposed, from small-scale models to complex 3D modeling using modern computational codes. The geometries are wide-ranging and deal with the narrowing and widening of sections (stenoses, aneurysms), bifurcations, geometries associated with prosthetic elements, and even cases of vessels with smaller dimensions than those of the blood cells circulating in them. Biological Flow in Large Vessels provides answers to the question of how medical and biomechanical knowledge can be combined to address clinical problems. It offers guidance for further development of numerical models, as well as experimental protocols applied to clinical research, with tools that can be used in real-time and at the patient’s bedside, for decision-making support, predicting the progression of pathologies, and planning personalized interventions. The first chapter on Hemodynamics and Hemorheology provides a state of the art introduction on blood and red blood cell rheology.