This in-depth investigation of Bardaisan of Edessa (†?222) and the Syriac Book of the Laws of Countries, written by leading experts, explores Bardaisan's arguments on intellect, free will, nature, fate, anthropology, astrology, and eschatology. The introduction by Ilaria L.E. Ramelli examines his school and works, presents the Book as a Platonic dialogue reflecting his thought, and analyses its arguments against "Gnosticism" and Marcionism. Following the edition, translation, and commentary, six essays present new research. The first two focus on Bardaisan's support for apokatastasis, highlight parallels with Origen, and examine their shared Middle Platonic framework. The remaining essays explore the work's historical and cultural context as well as its philosophical and astrological background. The final essay assesses Bardaisan's impact on late antique Christianity.