Positive pressure mechanical ventilation has gained widespread recognition as an essential strategy in the treatment of various forms of acute and chronic respiratory failure. Its mechanism directly or indirectly impacts respiratory physiology and respiratory musculature in various medical/surgical pathological conditions. In addition, it has been recognized as a factor that influences both short- and long-term prognosis of critically ill patients. This book selects hot topics on indications of mechanical ventilation, technological development advances, ethical and cost associated with mechanical ventilation. Initially, the authors believe an essential approach to positive pressure ventilation is based on physiology, modality of mechanical ventilators, ventilatory modes, and possible complications. The most important mechanical ventilation topics and advances made in critically mechanical ventilated patients include obesity, severe hypoxemic respiratory failure, cardiac surgery, lung/cardiac transplants, thoracic and brain trauma, pregnancy, and sleep breathing disorders. Patient-ventilator asynchrony, sedation and neuromuscular protocols in mechanical ventilation can be complicated by prolonged mechanical ventilation, weaning failure, sepsis and delirium. Continuous advances are being made in technologies such as diagnosis, monitoring and treatment patient-ventilator asynchrony, respiratory muscle function such as electromyography in diaphragm and lung function by ultrasound or electrical impedance. Finally, ethical and health-related cost perspectives of mechanical ventilation represent the last essential approach towards emergent issues in mechanical ventilation.