I couldn’t find a verified, legitimate PDF of “The Great Book of Music” ( Kitab al-Musiqa al-Kabir ) by Al-Farabi titled exactly as “the great book of music alfarabi pdf portable” that is freely and legally distributed. This 9th–10th century Arabic philosophical encyclopedia on music theory is a major scholarly work, but complete English translations are rare; most available texts are in Arabic or critical editions in German/French.
Written in the 10th century, Kitab al-Musiqa al-Kabir was commissioned by Abu Ja'far Muhammad ibn al-Qasim, the vizier of the Abbasid caliphate. Al-Farabi, often referred to as the "Second Teacher" (second only to Aristotle), sought to correct the deficiencies he found in existing Greek musical treatises that had been translated into Arabic. the great book of music alfarabi pdf portable