This timely book provides deep historical context for contemporary concerns with the ways in which the movement of Islamist ideas has radicalized Southeast Asia. The fourteen contributors represent the best of the new multilingual scholarship, drawing extensively on Arabic and Malay/Indonesian sources as well as those in Western languages. The authors reach back to the seventh century to explain how trade linked these eastern and western crossroads of Eurasia together, and how Islam provided an important idiom for their subsequent complex interactions. The book also explores and problematizes Islam as a trans-regional phenomenon, questioning the parameters of movement itself by showing that students, merchants and mullahs were all part of a constantly-shifting field of exchange. The Indian Ocean as a whole still bears a myriad imprints of their passage in both directions. There are no centers and no peripheries in this sophisticated interpretation of how waves of reform have affected both homelands. In its entirety, the book argues for taking a long-view approach to current-day problems, and sketches out the genealogies of contact, conflict, and accommodation over a thousand years.