What are the best books related to the obscure words of the Qur'an, its difficult points, and its grammar?

The questioner : What do you consider appropriate regarding the obscure words of the Qur'an, its difficult points, and its grammar?

The Shaykh : What is the matter with these things?

The questioner : The books, tell us.

The Shaykh : The books!

The questioner : The appropriate ones.

The Shaykh : The obscure words of the Qur'an?

The questioner : And its difficult points.

The Shaykh : And the difficult points of the Qur'an?

The questioner : And its grammar.

The Shaykh : And its grammar! The obscure words of the Qur'an by al-Isfahani, this is well known; the difficult points of the Qur'an by Ibn Qutaybah; the grammar of the Qur'an.

The questioner : Al-Nahhas, is he good? Abu Ja'far al-Nahhas.

The Shaykh : I do not know that Abu Ja'far al-Nahhas has one.

The questioner : He has, but.

The Shaykh : Grammar?

The questioner: Yes.

The Shaykh : Abu Ja'far al-Nahhas has the abrogating and the abrogated.

The questioner : The abrogating and the abrogated, yes, that is right.

The Shaykh : And does he have one on grammar as well?

The questioner : Grammar, I think, may Allah know best.

The Shaykh : I do not know.

The questioner : Well, if he is good?

The Shaykh : Yes, he is good.

The questioner : Now, what about the rest?

The Shaykh : There is one on the grammar of the Qur'an by a person, and by Allah, his name has slipped my mind.

The questioner : Al-Hamzani?

The Shaykh : His name has slipped my mind, it seems like al-Akhdari?

The questioner : Al-Hamzani, approximately.

The Shaykh : I do not remember, but.