This volume presents all aspects of delivery of oxygen to tissues and tumors in peer reviewed short articles.  Both overview and the most recent, advanced techniques for oxygen measurement are presented.   Articles and peer reviewers include those from leaders in their field.  Topics such as molecular signaling in the organismal and tumor response to low levels of local oxygenation, hypoxia inducible factor (HIF) , cancer metabolism, individual human and animal response to oxygen changes monitored by optical/near infrared spectroscopy/ tomography to novel electron resonance spectroscopy and spectroscopic imaging, instrumentation, progress in blood substitute research, retinal physiology, cellular hypoxia, mitochondrial function; brain oxygenation and function;  oxygen transport in sports, hypoxia in diseases and clinical care. Chapters 10 and 19 of this book are open access under a CC BY 4.0 license.