The Book of Knowledge (Kitab al-'ilm) is the foundation of Al-Ghazali's magnum opus, the Revival of the Religious Sciences or Ihya Ulum al-Din.
Here Al-Ghazali defines knowledge and its relation to faith, theology and jurisprudence. It elucidates these types of knowledge and the nature of the Islamic obligation to seek knowledge.
Throughout al-Ghazali engages the reader in a heartfelt discourse, as he offers proofs, examples and reasoning derived from the Qur'an and Hadith.