Averroes served multiple tenures as judge and produced multiple works in the fields of Islamic jurisprudence or legal theory. The only book that survives today is Bidāyat al-Mujtahid wa Nihāyat al-Muqtaṣid ("Primer of the Discretionary Scholar"). In this work he explains the differences of opinion (ikhtilaf) between the Sunni madhhabs (schools of Islamic jurisprudence) both in practice and in their underlying juristic principles, as well as the reason why they are inevitable. Despite his status as a Maliki judge, the book also discusses the opinion of other schools, including liberal and conservative ones. Other than this surviving text, bibliographical information shows he wrote a summary of Al-Ghazali's On Legal Theory of Muslim Jurisprudence (Al-Mustasfa) and tracts on sacrifices and land tax.