This episode of the World of Islam introduces the so-called Ikhwan al-Safa (The Brethren of Purity), a group of mysterious thinkers that produced a major encyclopedic philosophical work. We touch on Ismailism and the attempt to unify various forms of knowledge in classical Islam.  A History of Islamic Philosophy           by Majid FakhryIslamic Philosophy A-Z                          by Peter S. GroffIslamic Philosophy: an Introduction   by Oliver LeamanThe Cambridge Companion to Arabic Philosophy   Edited by P. Adamson/R.C. Taylor