Sharaf al-Din MasâÅ«di (6th/12th cent.) was a philosopher, astronomer, mathematician and logician. A native of Marw, he spent a large part of his life in Bukhara and Samarqand, Transoxiana. In Bukhara he had a number of debates with the philosopher and theologian Fakhr al-DÄ«n RÄzÄ« (d. 606/1210), described in the latterâs MunÄáºarÄt jarat fÄ« bilÄd MÄ warÄʾ al-nahr. From among his philosophical works, his critical notes to Avicennaâs (d. 428/1037) al-IshÄrÄt wal-tanbÄ«hÄt deserve special mention. In the sciences, he wrote a work on astronomy and geography called al-KifÄya fÄ« Ê¿ilm al-hayʾa. In the introduction to this work he explains that he composed it at the request of a friend and that it is based on the works of others, among then Ibn al-Haytham (d. ca. 432/1040-41) and KushyÄr b. LabbÄn (fl. late 4th/10th cent.). Afterwards, he translated it into Persianâthis time without mentioning his sourcesâcalling it JahÄni- dÄnish, published in this volume.