Kâtip Çelebi (كاتب جلبي) or Ḥājjī Khalīfa (حاجي خليفة) (1017 AH/1609 AD – 1068 AH/1657 AD) was a Turkish polymath and author of the 17th-century Ottoman Empire. He compiled a vast universal bibliographic encyclopaedia of books and sciences, the Kaşf az-Zunūn, and wrote many treatises and essays. “A deliberate and impartial historian… of extensive learning”, Franz Babinger hailed him "the greatest encyclopaedist among the Ottomans."
Writing with equal facility in Alsina-i Thalātha—the three languages of Ottoman imperial administration, Arabic, Turkish and Persian – principally in Arabic and then in Turkish, his native tongue— he also collaborated on translations from French and Latin. The German orientalist Gustav Flügel published Kaşf az-Zunūn in the original Arabic with parallel Latin translation, entitled Lexicon Bibliographicum et Encyclopaedicum (7 vols.) The orientalist Barthélemy d'Herbelot produced a French edition of the Kaşf az-Zunūn principally with additional material, in the great compendium, Bibliothèque Orientale.