These are what are in my library thus far:
Alfeyev, Hilarion. The Spiritual World of Isaac the Syrian: Spiritual World of Isaac the Syrian. With a Foreword by Kalistos Ware. Cistercian Studies 175. Cistercian Publications / Liturgical Press, 2000.
Bar Hebraeus. The Ecclesiastical Chronicle: An English Translation. Trans. David Wilmshurst. Gorgias Eastern Christian Studies 40. Gorgias Press, 2016.
publisher’s blurb: “The Ecclesiastical Chronicle of the Syriac Orthodox polymath Bar Hebraeus (†1286), an important Syriac text written in the last quarter of the 13th century, has long been recognised as a key source for the history of the Syriac Orthodox Church and the Church of the East.”
Baumer, Christoph. The Church of the East: An Illustrated History of Assyrian Christianity. I. B. Tauris, 2008.
Becker, Adam H. Fear of God and the Beginning of Wisdom: The School of Nisibis and the Development of Scholastic Culture in Late Antique Meopotamia. University of Pennsylania Press, 2006.
Brock, Sebastian, trans. and ed. The Syriac Fathers on Prayer and the Spiritual Life. Cistercian Publications, 1987.
Brock, Sebastian P. and Susan Ashbrook Harvey, trans. Holy Women of the Syrian Orient. With an Introduction by Sebastian P. Brock and Susan Ashbrook Harvey. Transformation of the Classical Heritage 13. University of California Press, 1987.
note: A revised second edition was released in 1998.
Brown, Laurence E. The Eclipse of Christianity in Asia: From the Time of Muhammed to the Fourteenth Century. Cambridge University Press, 1933.
Brown, Laurence E. The Indian Christians of St Thomas: an Account of the Ancient Syrian Church of Malabar. University Press, 1956.
Cochrane, Steve [A.]. Asia’s Forgotten Christian Story: Church of the East Monastic Mission in Ninth-Century Asia. Regnum Edinburgh Centenary Series. Fortress Press, 2019.
Driver, G. R. and Leonard Hodgson, trans. and ed. Nestorius: The Bazaar of Heracleides. Translated from the Syriac and edited with an Introduction, Notes and Appendices. Oxford University Press, 1925. Reprint: Wipf and Stock, 2002.
Ephrem the Syrian’s Hymns on the Unleavened Bread. Trans. and Intro. by J. Edward Walters. Texts from Christian Late Antiquity 30. Gorgias Press, 2012.
Frykenberg, Robert Eric. Christianity in India: From Beginnings to the Present. Oxford History of the Christian Church. Ed. Henry and Owen Chadwick. Oxford University Press, 2008.
Gather, Jill. Teachings on the Prayer of the Heart in the Greek and Syrian Fathers: The Significance of Body and Community. Gorgias Dissertations. Gorgians Studies in Early Christianity and Patristics 47. Gorgias Press, 2014.
Gillman, Ian & Hans-Joachim Klimkeit. Christians in Asia Before 1500. The University of Michigan Press, 1999. (also published by Routledge)
Godwin, R. Todd. Persian Christians at the Chinese Court: The Xi’an Stele and the Early Medieval Church of the East. I. B. Tauris, 2018.
Haddad, Robert M. Syrian Christians in a Muslim Society: An Interpretation. Princeton Studies on the Near East. Princeton Legacy Library. Princeton University Press, 1970, 2015.
Kitchen, Robert A., trans. The Discourses of Philoxenos of Mabbug: A New Translation and Introduction. Cistercian Studies 235. Cistercian Publications / Liturgical Press, 2014.
Mingana, Alphonse. The Early Spread of Christianity in Central Asia and the East: A New Document. Analecta Gorgiana 640. Gorgias Press, 2010. [reprint of 1925 first edition]
Moffett, Samuel Hugh. A History of Christianity in Asia; vol. 1: Beginnings to 1500. Orbis Books, 1998.
Moule, A. C. [Arthur Christopher]. Christians in China Before the Year 1550. Society for Promoting Christian Knowledge, 1930. Reprint edition: Martino Publishing, 2011.
Mundadan, A. M. History of Christianity in India; vol. I.: From the Beginning up to the middle of the sixteenth century. Church History Association of India, 1989.
Norris, Frederick W. Christianity: A Short Global History. London: OneWorld Publications, 2002.
Payne, Richard E. A State of Mixture: Christians, Zoroastrians, and Iranian Political Culture in Late Antiquity. Transformation of the Classical Heritage 56. University of California Press, 2015.
Penn, Michael Philip. Envisioning Islam: Syriac Christians and the Early Muslim World. University of Pennsylvania Press, 2015.
Roberts, Alexander and James Donaldson, eds. Gregory the Great II; Ephriam Syrus; Aphrahat. Vol. 13 in A Select Library of Nicene and Post-Nicene Fathers of the Christian Church, Series 2 (NPNF-2 13).
Sahner, Christian C. Christian Martyrs under Islam: Religious Violence and the Making of the Muslim World. Princeton University Press, 2018.
Saint-Laurent, Jeanne-Nichole Mellon. Missionary Stories and the Formation of the Syriac Churches. Transformation of the Classical Heritage 55. University of California Press, 2015.
Schaff, Phillip, and Henry Wace, eds. The Twelve Patriarchs, Excerpts and Epistles, The Clementia, Apocrypha, Decretals, Memoirs of Edessa and Syriac Documents, Remains of the First Age. Vol. 8 in Ante-Nicene Fathers: The Writings of the Fathers Down to A.D. 325 (ANF 8).
Smith, Kyle. Constantine and the Captive Christians of Persia: Martyrdom and Religious Identity in Late Antiquity. Transformation of the Classical Heritage 57. University of California Press, 2016.
Vine, Aubrey R. The Nestorian Churches: A Concise History of Nestorian Christianity In Asia From the Persian Schism to the Modern Assyrians. Foreword by Mar Eshai Shimun, Patriarch of The East. London: Independent Press, 1937.
Vööbus, Arthur. Hstory of Asceticism in the Syrian Orient: A Contribution to the History of Culture in the Near East. Vol. 1, The Origin of Asceticism: Early Monasticism in Persia. Secrétariat du CorpusSCU, 1958.
Ye’or, Bat. The Decline of Eastern Christianity Under Islam: From Jihad to Dhimmitude. Forward by Jacques Ellul. Trans. (from French) Miriam Kochan and David Littman. Associated University Presses, 1996.
And these remain on my wishlists:
Aphraates the Persian sage. The Demonstrations of Aphrahat, the Persian Sage. Trans. Adam Lehto. Gorgias Eastern Christian Studies 27. Gorgias Press, 2010.
Beggiani, Seely J. Early Syriac Theology: With Special Reference to the Maronite Tradition. University Press of America, 1983.
Beggiani, Seely. Introduction to Eastern Christian Spirituality: The Syriac Tradition. University of Scranton Press, 2005.
Brock, Sebastian. Fire from Heaven: Studies in Syriac Theology and Liturgy. Variorum Collected Studies 863. Routledge, 2006.
[This is a collection of 17 of Brock’s studies previously published elsewhere, but which are often rather inaccessible.]
Brock, Sebastian. The Luminous Eye: The Spiritual World Vision of Saint Ephrem the Syrian. Rev. ed. Cistercian Studies 124. Cistercian Publications, 1992.
Brock, Sebastian P., ed. and trans. The Martyrs of Mount Ber’ain. Intro. by Paul C. Dilley. Persian Martyr Acts in Syriac: Text and Translation 4. Ed. Adam H. Becker. Gorgias Press, 2015.
Brock, Sebastian P. Spirituality in the Syriac Tradition. Mōrān ’Eth’ō. Gorgias Press, 2012.
Brock, Sebastian. Studies in Syriac Spirituality. Rev. ed. Dharmaram Publications, 2008.
Brock, Sebastian P. Treasure-house of Mysteries: Explorations of the Sacred Text Through Poetry in the Syriac Tradition. Popular Patristics 45. St Vladimir’s Seminary Press (aka SVS Press), 2012.
Brock, Sebastian P. The Wisdom of Isaac of Nineveh: A Bilingual Edition. Texts from Christian Late Antiquity 1. (English and Syriac Edition) Gorgias Press, 2006.
Cochrane, Steve. Many Monks Across the Sea: Church of the East Monastic Mission in Ninth-Century Asia. Regnum Studies in Mission. Regnum, 2017.
Colless, Brian E., trans. The Wisdom of The Pearlers: An Anthology of Syriac Christian Mysticism. Intro. by Brian E. Colless. Cistercian Studies 216. Cistercian Publications, 2008.
Drijvers, H. J. W. East of Antioch: Studies in Early Syriac Christianity. Variorum Reprints, 1984.
Ephraem Syrus. Ephrem the Syrian: Hymns. Trans. and intro, by Kathleen E. McVey.
Preface by John Meyendorff. Classics of Western Spirituality. Paulist Press, 1989.
Ephrem the Syrian. St. Ephrem the Syrian: Hymns On Paradise. Trans. Sebastian Brock. St Vladimir’s Seminary Press, 1997.
Ephrem the Syrian. The Harp of the Spirit: Poems of Saint Ephrem the Syrian. Publications of the Institute for Orthodox Christian Studies (Cambridge) 1. Trans. and intro. by Sebastian Brock. 3rd ed. Aquila Books, 2013.
Herman, Geoffrey, ed. and trans. Persian Martyr Acts under King Yazdgird I. Persian Martyr Acts in Syriac: Text and Translation 5. Gorgias Press, 2016.
King, Daniel, ed. The Syriac World. Routledge, 2018.
Kitchen, Robert A., trans. Kitchen, Robert A., trans. The Book of Steps: The Syriac Liber Graduum. Cistercian Studies 196. Cistercian Publications, 2004.
Miller, Robert. Syriac and Antiochian Exegesis and Biblical Theology for the 3rd Millennium. Gorgias Eastern Christian Studies 6. Gorgias Press, 2008.
Sahner, Christian C. Christian Martyrs under Islam: Religious Violence and the Making of the Muslim World. Princeton University Press, 2018.
Schor, Adam M. Theodoret’s People: Social Networks and Religious Conflict in Late Roman Syria. University of California Press, 2011,
Shemunkasho, Aho. Healing in the Theology of Saint Ephrem. Gorgias Dissertations 1. Gorgias Studies in Early Christianity and Patristics. Gorgias Press, 2004. [Reprinted as paperback, 2014.]
Tang, Li. East Syriac Christianity in Mongol-Yuan China (12th-14th centuries). Orientalia Biblica et Christiana 18. Harrassowitz Verlag, 2011.
Tang, Li and Dietmar W. Winkler, eds. Winds of Jingjiao: Studies on Syriac Christianity in China and Central Asia. Orientalia – Patristica – Oecumenica 9. LIT Verlag, 2016.
Thomas, Davis, ed. Syrian Christians Under Islam: The First Thousand Years. Brill, 2001.
Winkler, Dietmar W. and Li Tang, eds. Hidden Treasures and Intercultural Encounters: Studies on East Syriac Christianity in China and Central Asia. Orientalia – Patristica – Oecumenica 1. LIT Verlag, 2009.
Yacoub, Joseph. Year of the Sword: The Assyrian Christian Genocide, A History. Trans. James Ferguson. Oxford University Press, 2016.