How can reliable religious books be chosen from the Doha Book Fair to learn about the rulings of the abrogating and abrogated (nāsikh wa-mansūkh) and the principle of "the lesson is in the generality of the wording" (al-ʿibra bi-ʿumūm al-lafẓ)?

Abrogation occurred in the Qur'an and the Sunnah. Among the best books authored on abrogation in the Qur'an are: Al-Naskh fi al-Qur'an al-Karim - Dirasah Tashri'iyyah Tarikhiyyah Naqdiyyah by Mustafa Zayd, and Al-Ayat al-Mansukhah fi al-Qur'an al-Karim by Abdullah al-Shinqiti. Among the most important books on abrogation in the Sunnah are: Al-I'tibar fi Bayan al-Nasikh wal-Mansukh min al-Athar by Al-Hazimi, and I'lam al-'Alim Ba'da Rusukhahu bi Haqa'iq Nasikh al-Hadith wa Mansukhuhu by Ibn al-Jawzi.

As for books on jurisprudential maxims (qawa'id fiqhiyyah), they are numerous. For beginners, there are: Manzumat al-Qawa'id al-Fiqhiyyah by Al-Sa'di, and Sharh Manzumat Usul al-Fiqh wa Qawa'idih by Ibn 'Uthaymin. For intermediate students: Al-Wajiz fi al-Qawa'id al-Fiqhiyyah by Al-Bourno. For advanced students: Al-Ashbah wal-Naza'ir by Al-Suyuti.

Fundamental principles (qawa'id usuliyyah) are mentioned in works on the principles of Islamic jurisprudence (usul al-fiqh). Among the easiest of these books are: Al-Usul min 'Ilm al-Usul by Ibn 'Uthaymin, and Al-Wadih fi Usul al-Fiqh lil-Mubtadi'in by Al-Ashqar. It is advisable to focus on fiqh before jurisprudential maxims.