Ruling on taking books by stealth from his grandfather to learn from them and keep them
Question

I have a grandfather who is stingy with his property… He has quite a few useful books that he bought when he was young, including some useful Islamic books, some of which are out of print and not available in the market. I am a seeker of knowledge, and I want to make use of them, but he will not let me do that. Is it permissible for me to take them by stealth and make use of them and keep them?
Praise be to Allah.It is not permissible to transgress against the property of another person by stealing, plundering, seizing by force or taking it without his permission, even if that is by way of borrowing. The ruling on the books in this regard is the same as the ruling on other kinds of property, hence the majority of scholars ruled that the hand of one who steals them is to be cut off.
Ibn Qudamah (may Allah have mercy on him) said in al-Mughni (9/98): If he steals a Mus-haf, Abu Bakr and al-Qadi said: His hand is not to be cut off for that. This is the view of Abu Hanifah…
Abu’l-Khattab favoured the view that his hand is to be cut off, and he said: This is the apparent meaning of the words of Ahmad. He was asked about someone who stole a book containing knowledge to study it, and he said: Anything of which the value reaches three dirhams, the hand of the one who steals it is to be cut off. This is the view of Malik, ash-Shafa‘i, Abu Thawr and Ibn al-Mundhir, because of the general meaning of the verses which speak about all thieves.…
There is no difference of opinion among our companions regarding the fact that the hand of the thief is to be cut off for stealing books of jurisprudence, hadith and all other Islamic sciences.
It says in al-Mawsu ‘ah al-Fiqhiyyah (34/193): The Malikis, Shafa‘is and Hanbalis, and Abu Yusuf among the Hanafis, are of the view that the hand of one who steals a beneficial book – such as a book of tafsir, hadith, jurisprudence or other beneficial sciences – is to be cut off, if the value of the stolen item reaches the minimum threshold. End quote.
So you have no right to take these books by stealth, or to keep them. Rather you must ask permission, then if he gives you permission and lets you borrow them, all well and good, otherwise you have no right to take them. The Prophet (blessings and peace of Allah be upon him) said: “It is not permissible to take the property of anyone unless he gives it willingly.” Narrated by Ahmad (20172); classed as sahih by al-Albani in Sahih al-Jami‘ (7662).
This is not the only way to seek knowledge. You can come to an agreement with your grandfather to go to his house and read the books there, and not take them away.
Or you can go to the public library, where – in sha Allah – you will find many useful books.
And Allah knows best.