Breathing is usually automatic and without conscious effort; yet our breathing is a complex motor function requiring the coordinated activation of a number of respiratory muscles that span from our heads to our abdomen. Some of our respiratory muscles serve to pump air into and out of our lungs (ventilation). These pump muscles act on the thoracic and abdominal walls and are all skeletal muscles. Other respiratory muscles in our bodies control the caliber of the passageway for air to enter our lungs. These airway muscles include skeletal muscles of the head (e.g., tongue and suprahyoid muscles) and neck (infrahyoid, pharyngeal and laryngeal muscles), as well as smooth muscles that line our trachea and bronchi down to the alveoli where gas exchange occurs. This book provides an overview of the anatomy and physiology of our respiratory muscles, including their neural control. This book also includes an overview of the basic structure and function of both skeletal and smooth muscles. The two basic types of respiratory muscles (skeletal and smooth muscle) vary considerably in the organization of their contractile proteins and the underlying mechanisms that lead to force generation and contraction, including their neural control.