This book is written primarily with the intent of helping medical residents understand the basics of mechanical ventilation. It is meant to be read during a one-month rotation in the ICU. It is a compilation of concepts and explanations that were formed during teaching rounds in the ICU at St. Francis Hospital in Evanston, IL. As residents and students would ask questions regarding the ventilator, I was compelled to answer those questions in a manner that was practical for the resident. As a result, this book is somewhat unique, in that its content was developed in response to those questions, and is therefore tailored to the needs of residents in training. Included are chapters on sedation in the ICU and neuromuscular blockade.