This book is an introduction to a comprehensive analysis of recent advances and clinical research in noninvasive mechanical ventilation (NIV) in Pulmonary, Critical Care, and Sleep Medicine. The objective of the book is to increase the knowledge and understanding of the reader in the best clinical practice in three main sections. A selected international group of experts in the field of noninvasive ventilation formed a panel to provide an update on the recent literature in the application and efficient utilization of NIV in Pulmonary, Critical Care, and Sleep Medicine. Each particular section will discuss the application of NIV in different disease process. The authors summarized the main results of the recent trials, clinical and technological advances, expert opinions, and practical guidelines.