Katip Celebi

Mustafa ibn Abdullah, known as Katip Celebi (1017-1067H / 1609-1657 CE) or Haji Khalifa, was one of the most remarkable Ottoman scholars. A professional accountant (katip) who educated himself through voracious self-study, he wrote Kashf al-Zunun 'an Asami al-Kutub wa al-Funun, the most comprehensive Islamic bibliographic encyclopedia, listing some 15,000 book titles across all Islamic sciences with brief descriptions — an incomparable reference tool. He also wrote Jihannuma (on geography and cartography, incorporating European maps), Fezleke (Ottoman history), and other works. He advocated engagement with European sciences and is considered a precursor of Ottoman reform.