This important work by the Persian polymath Muḥammad b. Aḥmad, who is better known as Abū Rayḥān "al-Bīrūnī" al-Khwārazmī (d. 440 A.H., 1048 C.E.) was written originally in circa 390 A.H. (1000 A.D.). The manuscript has a distinct multi-ethnic and multi-confessional flavour. Al-Bīrūnī, who calculated on the basis of measurements he took in the Punjab plain that the world was round, describes the systems of calculating time used by the known races of the world, and their associated festivals.

The present copy is one of the oldest and is an important example of medieval Persian book painting. Its text and 26 illustrations breathe a spirit of tolerance and open-eyed curiosity about the world at large. Christian scenes (the Baptism and the Annunciation) complement Islamic images including scenes from the life of the Prophet Muḥammad, as well as others of Zoroastrian, pre-Islamic Arabian, Jewish and Hindu origin, and even one of the birth of Julius Caesar.

The title page decoration and illustrations feature both gold and colour.