The aim of this ISCCM manual is to focus on the noninvasive ventilation. Noninvasive ventilation (NIV), as a technique/intervention, is universally practiced by pulmonologists, intensivists, emergency physicians and anesthesiologists in different environments in varied conditions. Its use has expanded multifold over the years because of ease of application, cost effectiveness and flexibility. This book comprised of 8 sections that include introduction and physiology, noninvasive ventilation: disease specific, noninvasive ventilation in specific situations, monitoring and weaning, problems with noninvasive ventilation, home ventilation, high flow nasal cannula, and neonatology and pediatrics, which are further divided into 41 chapters. Chapters in the manual under different sections heads dealing with physiology, clinical applications, use in different types of respiratory failure, including end of life situations, and limitations, challenges as well as its use in pediatrics. In this book, evidence-based and updated protocols have been used in easy to read format with flowcharts and diagrams. This book will be helpful to all postgraduates, intensivists and physicians.