The Dustūr al-Munajjimīn is one of the few surviving Ismaili books dating back to the period of Ḥasan-i Ṣabbāḥ. This volume analyses the provenance and content of the only manuscript of the text and provides information on its origin and composition. By combining articles on astronomy and historiography, the volume furthermore draws a more general picture of the intellectual activities during the 11th and 12th century and their interrelation on a local as well as supra-regional level with a special focus on the Ismailiyya.