From the 39^th annual conference of the International Society on Oxygen Transport to Tissue (ISOTT), held in Washington, DC, USA in July 2011, this volume covers aspects of oxygen transport from air to the cells, organs and organisms; instrumentation and methods to sense oxygen and clinical evidence. This volume of Oxygen Transport to Tissues studies near infrared spectroscopy, brain oxygenation, tumor biology, angiogenesis and mitochondrial metabolism, systems modeling, gas transport, kidney and exercise physiology. Emphasis is placed on methods of oxygen measurement in living tissue and application of these technologies to understanding physiological and biological bases for pathology related to tissue oxygenation. This multidisciplinary volume includes contributions from scientists (physicists, biologists and chemists), engineers, clinicians and mathematicians.