It may be a cliché, but the solitary endeavour of writing a book like this would never be accomplished without the support and motivation of others. Besides to the publisher, who gave me the opportunity to publish this volume, my sincere thanks go to the following persons who, in one way or the other, have contributed to my research. In the first place, my gratitude goes to my original Ph.D. supervisor, prof. dr. Gie Vleugels, who introduced me to Narsai and encouraged me to continue studying Syriac. He was always a joy to converse with and his trust in my capabilities felt like being wrapped in a warm blanket. Unfortunately, he was forced into an early retirement because of ilness. Equally inspiring were my other promoters, prof. dr. Donald Fairbairn—who accepted me as a student in the final phase of the project—and prof. dr. Paul van Geest. Their enthusiasm heartened me throughout the project. I am grateful to prof. dr. Paul van Geest for giving me the opportunity to embed my research into the Mystagogy Project of the Centre for Patristic Research. Others who crossed my path and walked with me one or more steps are (in alphabetical order) dr. Kees den Biesen, prof. dr. Judith Frishman, prof. dr. Gerard Rouwhorst, Mor Polycarpus Augin Aydin, prof. dr. Bas Ter Haar-Romeny, and Charis Vleugels. Special thanks goes to dr. Sebastian Brock, who never got tired of answering my e-mails and sharing his thoughts on a wide range of topics. To Marten Vogelaar, Henk de Oude, and Donald Fairbairn I am indebted for editing my English. The latter also supplied me with valuable advice during the final phase of preparing the manuscript for publication. Next, my gratitude goes to my employer for granting me study leave in order to work on this project. Finally, I want to thank my dear wife Elisabeth and son Levi for their love, sacrifice, patience, support, and understanding.