This first monograph-length treatment of the Syriac Letter of the Stoic Mara bar Sarapion of Samosata to his son contains a critically edited text, English and German translations, and notes on language, syntax, cultural background, and parallels from ancient literature, along with an introduction and essays on central questions of interpretation. These include the letter's linguistic position within Aramaic literature and the form-critical location of the text within the genre of Hellenistic epistolography. The most probable historical context is identified as the Roman-Commagenean war (72 CE). The mention of the "wise king of the Jews" in a series of paradigmatic philosophical figures occasions a discussion of the relationship of this cultured citizen of Commagene to Judaism and early Christianity. Mara's lucid argumentation is located within the philosophical discourse of the imperial era.