This volume is a little-known work of Samarqandi, having been not mentioned in any of the traditional sources. This book was evidently compiled during the later stage of the author`s life and probably at the request of a state official called Zaki ’Ibrahim, to whom Samarqandi also dedicated his commentary on Qistas in 692/1293. As stated in the work, the author had been in Tabriz in 688/1289, which implies that it was written after that date. The "‘Ilm al-’afaq wa al-’anfus," as the name explicitly suggests, contains two categories of sciences: one concerns the external world, and the other is related to the internal world. The work, then, includes most of the author`s thoughts concerning philosophy, physics and Sufism. The two categories, however, are elaborately integrated into a unified science called ‘‘science of the cosmos and the soul,’’ a name having been coined, as Samarqandi holds in the introduction, by the Leader of believers, ‘Ali. The work, therefore, should not be compared with encyclopedic writings such as Jami‘ al-‘ulum of Fakhr al-Din Razi, Durrat al-taj of Qutb al-Din Shirazi (d. 710/1310) and Nafa’is al-funun of Shams al-Din Muhammad Amuli (d. 753/1352), because, though it consists of several parts, each of which is in turn an independent science, the author provides one subject and one end or telos for all the parts. NOTE:Main Text in Persian and Arabic; Introduction in English.