Jābir ibn Ḥayyān (Arabic/Persian: جَابِر ٱبْن حَيَّان, died c. 806−816), known by the kunyas Abū Mūsā or Abū ‘Abd Allāh and the nisbas al-Ṣūfī, al-Azdī, al-Kūfī, or al-Ṭūsī, is the supposed author of an enormous number and variety of works in Arabic often called the Jabirian corpus. The scope of the corpus is vast and diverse covering a wide range of topics, including alchemy, cosmology, numerology, astrology, medicine, magic, mysticism, and philosophy. Popularly known as the father of chemistry, Jabir’s works contain the oldest known systematic classification of chemical substances, and the oldest known instructions for deriving an inorganic compound (sal ammoniac or ammonium chloride) from organic substances (such as plants, blood, and hair) by chemical means. As early as the 10th century, the identity and exact corpus of works of Jabir was in dispute in Islamic circles. The authorship of all these works by a single figure, and even the existence of a historical Jabir, are also doubted by modern scholars. Instead, Jabir ibn Hayyan is seen more like a pseudonym to whom “underground writings” by various authors became ascribed. Some Arabic Jabirian works (e.g., the “Book of Mercy”, and the “Book of Seventy”) were translated into Latin under the Latinized name “Geber”, and in 13th-century Europe an anonymous writer, usually referred to as pseudo-Geber, started to produce alchemical and metallurgical writings under this name.