Dr. Akos Koller has started his research work in Hungary after finishing the Semmelweis Medical School in 1969-1975. Then, he started to work on coronary and brain microcirculation with Prof AGB Kovach. He moved from Hungary to the USA in 1982, where he was doing research at the Cerebrovascular Res Center at University of Pennsylvania, with Martin Reivich and Britton Chance on pial microcirculation, regarding the role of adenosine, NADH level/metabolism and spreading depression. He then went to Tucson, Arizona where he learned from Paul C Johnson all topics of classical in vivo microcirculation and engaged in microcirculatory network studies to understand important complexity of microcirculation. Then in 1987, he moved to Valhalla, New York, where he was studying the function of microvessels of various tissues, the newly discovered vasomotor role of endothelium in vivo and the effect of hemodynamic forces in acute and chronic condition on the remodeling of microvascular function in vitro. In 1989, he discovered the role of wall shear stress in eliciting substantial dilation of arterioles, venules and affecting the vasomotion of lymphatic microvessels. Later he investigated the modulation of the function of endothelium by age, gender, exercise and various diseased conditions. He then in 2011 discovered that increases in flow elicit constrictions in cerebral arteries contributing thereby to the autoregulation of cerebral blood flow and clarified the underlying molecular signaling. In 2019 he has received the prestigious Malpighi Award of the European Society for Microcirculation. Total IF: 922.4, Citations: 9969, Hirsch index: 62.