Thousands of patients present to emergency departments each year for medical treatment, and the first person they are greeted by is the triage nurse. The role of the triage nurse is to assess patients as they arrive and determine the priority of care. This book looks at the history of triage from the first rudimentary form of triage by Baron Dominique Jean Larrey stepping through the world wars, and looking at triage systems in use today. Triage today has evolved from the military form of triage, and is used in emergency departments throughout the world. This book describes four of the triage systems used in The United States of America, Canada, United Kingdom and Australia. The triage nurse requires excellent communication skills, compassion and a sound knowledge base to be able to carry out their role; they also require critical thinking skills. The book looks at critical thinking and why it is an important skill every triage nurse requires.