Ibn Rusta's Kit?b al-A?l?q al-nafisa and Kit?b al-Buld?n by al-Ya?q?b?

Abu ?Al? A?mad b. ?Umar Ibn Rusta was born in Isfahan at an unknown date and he flourished in the first decade of the 10th century CE. Only the seventh volume of his Kit?b al-A?l?q al-naf?sa has survived. The work deals with mathematical, descriptive and human geography and a variety of historical and other subjects. One of his sources seems to have been a more complete version of Ibn Khurrad?dhbih, which has not survived. The Kit?b al-A?l?q al-naf?sa, which has been characterized as an encyclopedia of geographical knowledge, is a rich source on the kinds of subjects that interested the cultivated classes of ?Abb?sid society. It is published here together with the Kit?b al-buld?n ('The book of countries') by al-Ya?q?b? (d. c. 905 CE). al-Ya?q?b?'s Kit?b al-buld?n is an administrative geography based in part on the author's extensive travels, which also contains valuable historical data. For instance, it provides the earliest information about the political history and state-building of the Sudan west of the Nile.