Non-invasive ventilation (NIV) has shown, in the last two decades, to be an essential ventilatory management modality for treatment of patients with diverse etiologies of acute and chronic respiratory insufficiency, with significant favorable outcomes in terms of improvement in gas exchange, respiratory muscle fatigue, and dyspnea. NIV is an alternative to invasive mechanical ventilation, with significant improvement in short and long term prognosis. However, despite the abundance of literature supporting the benefits of NIV, there is controversy in regards to the timing of initiation and termination of NIV in the disease process, leading to unsettled issues and constant analysis for both researchers and physicians in clinical practice. There is scarce literature that describes thorough predictors of success or failure of NIV. There is need to develop tools or models to predict response to NIV, optimise those responses, increase tolerance to NIV technology (mechanical ventilator, interface, or ventilatory mode) that can be translated to increase success rate of NIV. The book Non-Invasive Ventilation: A Practical Handbook for Understanding the Causes of Treatment Success and Failure is the first text published with well-defined objectives that analyze the success and failure response of non-invasive mechanical ventilation. The table of contents is structured in an order to meet the defined objectives based upon respiratory physiology: Breathing patterns; Respiratory muscular fatigue (inspiratory / expiratory muscle); Lung mechanics (compliance and airway resistance); Gas exchange (hypercapnic/hypoxemic), and neurologic determinants). Sections of this book will address different aspects of NIV ranging from perspective pathophysiological benchmarks and clinical studies, to diagnosis and monitoring elements of basic lung-patient-ventilator interaction, including: Monitoring lung mechanics (pressure curves, volume (tidal and minute) (lower and high) and leakages (concept / monitoring), in a broad and profound way illustrating potential determinants and scenarios in non-invasive-ventilation. The aim is to describe a summary of global and practical recommendations of the utility of NIV that will affect the reader’s capability in treating respiratory comorbidities. These include: Chronic respiratory diseases like obstructive sleep apnea; Obesity hypoventilation syndrome and Cardiac chronic insufficiency.