ABSTRACT
This article was created by combining the articles ‘Kâtib Çelebi’ (Ankara, 2002, Türkiye Diyanet Vakfı Yayınları, vol. 25, pp. 36-40) and ‘Düstûrü'l-Amel’ (Ankara, 1994, Türkiye Diyanet Vakfı Yayınları, vol. 10, pp. 50-51) written by Orhan Şaik Gökyay for the Encyclopaedia of Islam. These articles are quoted verbatim and only their bibliographies are combined.