Al-Tha'alibi's classical work - Secret of Arab Philology - an important dictionary and thesaurus, carefully researched and arranged with references to sources such as Quran, Hadith, Arab proverbs, and more. By Abd al-Malik bin Muhammad bin Ismail (ca, 350/961 - 429/1038), known as Abu Mansur Tha'alibi al-Nisabure, the Arabic language expert in grammar, and meanings and usage of words and terms.