ISBN-13: 9780198823339 / Angielski / Twarda / 2019 / 600 str.
This volume presents three of the Epistles of the Brethren of Purity, a monumental work of medieval Islamic learning. Epistle 49 explores the hierarchy of existence; Epistle 50 describes the proper attitudes towards body and soul; Epistle 51 considers the arrangement of the world on numerical principles.