Paul E. Walker looks at this seminally important Ismaili missionary from the tenth century (Islamic fourth century) from a fresh perspective. Al-Sijistani and his thought are presented in this book much as he might have done himself if he had written for a more modern audience. Though long neglected by historians of Islamic philosophy, al-Sijistani’s recently recovered writings prove that he deserves careful consideration both as a philosopher and as an exponent of the intellectual understanding of Islam.

The old problem of the meaning of science and religion and their interactions as reflected in the thought of an Ismaili author from a remote period is now interpreted within a framework that provides broad coherence to disparate ideas and obscure doctrines which survive only piecemeal from medieval Arabic books and treatises. Here, al-Sijistani’s contributions appear all the more cogent and impressive, despite the distance of the thousand years that separate him from us.