Al-Ihkam fi Usul al-Ahkam - al-Amidi (2 vol.)

This work of Ibn Hazm deals with Usul al-Fiqh very detailed and thorough, very rich evidence from the Qur'an and the Sunnah and hammering the importance of sticking on both in everything.

The book covers all chapters of Usool as evidences, judgments, the use of texts, orders, prohibitions, the general and the specific, the abrogating and the abrogated, the analogy, consensus and many other topics.