Translated from the Arabic.
English text has xxv, 201 p.
Epistles of the Brethren of purity : On logic : an Arabic critical edition and English translation of Epistles 10-14 by Ikhwān al-Ṣafāʾ. ISBN 9780199586523. Published by Oxford University Press in 2010. Publication and catalogue information, links to buy online and reader comments.