Boyle Abbey is a National Monument in the town of Boyle, Roscommon. It was the principal Cistercian house in the kingdom of Connacht in the medieval period and its ruins today are among the best preserved of the order to be found in the country. In 2006, the Office of Public Works commenced a major program of conservation works on the abbey, which involved dismantling and restoring the north aisle wall of the church, which had bowed. This was one of the largest stone conservation projects undertaken by the state and involved a multi-disciplinary team of experts, including engineers, architects, and archaeologists. These works produced a vast body of new information on the history, architecture, and archaeology of Boyle Abbey, which is presented in this volume.