In Doubts on Avicenna , Ayman Shihadeh offers an extended study and critical edition of Sharaf al-Dīn al-Masʿūdī's al-Mabāḥith wa-l-Shukūk , a key and hitherto unstudied source for twelfth-century Arabic philosophy. This text inaugurates the long commentarial tradition on Avicenna's Ishārāt .