Growing evidence has suggested that the adhesion of red blood cells (RBCs) to blood vessel wall endothelial cells (ECs) is a potent catalyst of microcirculatory disorders, but direct in vivo documentation has been lacking. In a recent study we have demonstrated the elevation of vascular resistance by RBCs with increased adhesion to ECs and normal deformability in the absence of aggregation. Unlike the previous chapter (i.e., the "point"), the findings and considerations discussed in this chapter (the "counterpoint) imply that RBC/EC adhesion is a more potent determinant of circulatory disorders than RBC aggregation.