Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The MIM-104 Patriot is a surface-to-air missile system, used by the United States Army and several allied nations as the primary high to medium air defense and medium tactical air defense system. In addition to these roles, Patriot has been given the function of the U.S. Army's anti-ballistic missile system, which is now Patriot's primary mission. Learn more about the MIM-104 Patriot system, its capabilities and purposes in the following pages.