A thorough knowledge of anesthesia equipment and breathing systems, along with appropriate maintenance and trouble-shooting techniques, is vital. This is best expressed by this quote: “The integrity of the anesthesia system is a critical part of the entire anesthesia process. An effective way to organize the understanding of all of the components of anesthesia equipment is to trace the flow of oxygen through the system. It continues to move through the flowmeter, vaporizer, and the fresh gas outlet, into the breathing system and to the patient. The chapter discusses the main components of the anesthesia machine. The anesthesia machine, along with the oxygen source and the vaporizer, is designed to deliver a precise, but changeable, mixture of anesthetic gas and oxygen at a safe pressure and flow to a breathing system, which in turn delivers anesthetic gas and oxygen to a patient.