Among the most outstanding Ismaili thinkers, Hamid al-Din al-Kirmani was at the forefront of the intellectual advances of his time and almost on a par with his famous contemporary, Ibn Sina, with whom he shared many philosophical ideas. His ideas on the intellect and the order of creation are a departure from those expressed by early Ismaili thinkers which he endeavoured to amend, thus providing insights into to early Ismaili debates about philosophical and scientific concepts. This book presents a systematic investigation of al-Kirmani's life and thought. It focuses on the principal themes of his writings: the nature of human recognition and veneration of God; an understanding of the cosmic order; and the repose and tranquillity of the intellect. The author also examines a number of problems in the biography of al-Kirmani, the affiliations between his metaphysical system of thought and those of al-Farabi and Ibn Sina, and the importance of his writings for the Ismaili da'wa during the late-10th and 11th centuries.