In intensive care unit, the care of critically ill patients is a primary component of modern medicine. Intensive care units create potential for recovery in patients who otherwise may not have survived. They are, however, linked to the problem of nosocomial infections. The ventilator associated pneumonia (VAP) is one of the hospital acquired infections and may become life threatening not prevented. Various techniques are used to investigate and diagnose VAP. This book covers all the necessary information to understand the VAP with respect to pathophysiology, microbiology, diagnostic techniques and pharmacological treatment options.