Osamu Otsuka is Associate Professor of Asian and African History at The University of Tokyo. He is the author of numerous books, chapter and articles in Japanese and English, including a jointly authored chapter, The Dustur a'l-Munajjimin as a Source of Early Ismaili History', in Orthmann & Schmidl (eds), Sciences in the City of Fortune: The Dustur al-Munajjimin and Its World (EB-Verlag, 2017) and articles in Journal of Persianate Studies, Studia Iranica, The Journal of Oriental Researchers and Bulletin of the Society for Near Eastern Studies in Japan.