The surge in COVID-19 cases leading to hospitalizations around the world quickly depleted hospital resources and reserves, forcing physicians to make extremely difficult life-or-death decisions on ventilator allocation between patients.Leaders in academia and industry have developed numerous ventilator support systems using both consumer- and industry-grade hardware to sustain life and to provide intermediate respiratory relief for hospitalized patients.This book is the first of its kind to discuss the respiratory pathophysiology underlying COVID-19, explain ventilator mechanics, provide and evaluate a repository of innovative ventilator support devices conceived amid the pandemic, and explain both hardware and software components necessary to develop an inexpensive ventilator support device.This book serves both as a historical record of the collaborative and innovative response to the anticipated ventilator shortage during the COVID-19 pandemic and as a guide for physicians, engineers, and DIY'ers interested in developing inexpensive transitory ventilator support devices.