This third volume of the Humayma Excavation Project presents the most thorough excavation report and analysis of a Roman frontier fort yet published. Humayma, ancient Hawar or Hawara, began life as a small Nabataean settlement in the Hisma desert of Southern Jordan, 80 km south of Petra. Soon after the Roman conquest of the Nabataean kingdom in 106 CE, the town was incorporated into the new Provincia Arabia as Hauarra, and a fort was built on the slope above the original settlement. Hauarra flourished through the Byzantine period and in the late seventh century was purchased by the Abbasid family, which built an elaborately frescoed manor house and mosque. Henceforth known as al-Humayma, the town withered away after the Abbasids moved to Iraq in 749 and led the revolt against the Umayyad caliphate. Oleson began excavation in the fort with a small probe in 1987, followed by 10 seasons of extensive excavation and geophysical survey between 1993 and 2005, and a follow-up campaign by Reeves in 2012. The excavations provided important new information about the process of the Trajanic conquest of the Nabataean kingdom, the development of Roman military fortification design, the organization of the southern portion of the Provincia Arabia and adjacent frontier of the empire, and relations between Nabataean town dwellers and their Roman occupiers from the second through the fifth centuries.