Ultrasound has rapidly become integral to the practice of emergency medicine. Over the past few years, with improvements in device size and cost, there has been increasing interest in exploring the utility of ultrasound in the prehospital environment. Much of the available literature on ultrasound in the emergency setting focuses on care delivered in emergency departments and intensive care units within the developed world. As a result, most resources are inappropriate and inadequate for doctors and non-physicians practicing in out-of-hospital environments that, by definition, are resource limited. This manual fills that gap by focusing on simplified discussions of ultrasound studies, ultrasound physics, and research that impacts out-of-hospital care in order to meet the needs of prehospital and austere providers. The manual discusses the use of ultrasound for diagnosis in out-of-hospital care, advanced noninvasive monitoring of patients, and safety in performing procedures common to the prehospital and austere environment. As is the approach for prehospital education, the chapters are complaint based and not diagnosis based where applicable. Chapters cover ultrasound image interpretation and basic physics; common image adjustments to improve image quality; unique challenges found in urban prehospital environments, austere/wilderness environments, tactical environments, and military special operations environments; and initial training, quality improvement/assurance programs, and credentialing. It also includes a section on procedures such as pericardiocentesis, vascular access, cricothyroidotomy, and others specific to austere providers. The Manual of Austere and Prehospital Ultrasound is an essential resource for physicians and related professionals, residents, and medical students in emergency medicine, civilian and military EMS providers, and critical care flight paramedics and nurses.