Marcus Tso uses an interdisciplinary methodology to reexamine a long-neglected subject. Rather than the contents of ethics, the author focuses on the bases of ethics in the Qumran community, using the texts it collected as the primary evidence. He begins by comparing the ethical language of the Scrolls with other related literatures, then places the discussion in a historical framework based on recent findings. With the central chapters of the thesis, he explores four interrelated bases of Qumran ethics: e.g., how scriptural tradition(s) supported sectarian moral cosmology and halakhah; how identity formation informed both moral obligations and virtues; how cultural/political contexts may explain foreign ethical influences at Qumran, or their changing stance on violence; and how eschatology served as moral motivation. Furthermore, Marcus Tso confirms but qualifies some fundamental principles of Qumran ethics noted by earlier scholars, such as theonomy, naturalism, dualism, determinism, and rigorism.