Kitāb an-Nawāmīs (The Book of Laws), an anonymous tenth-century philosophical work attributed to Plato, constitutes a rare example of pre-Avicennan Arabic philosophy, combining Neoplatonic metaphysics and illustrative stories set in ancient Greece with the piety and ethical principles of early Islam. This study offers edition, translation and commentary of Kitāb an-Nawāmīs, and highlights the role the work played in the medieval Islamic reception of Platonism, as well as its impact on later philosophical discourses in Safavid Iran (1501-1722). The study thus adds to our understanding of the development of early Arabic philosophy, the transmission of antique Greek philosophical works into the Islamic tradition, and the medieval reception of Platonism more broadly.