Lost and found items: Taking some books left at a mosque

Question
In one of the mosques in our locality there are some very valuable books which no one reads. It looks as if they belong to someone who used to read them but left them in the mosque or forgot them. I know these books belong to someone because they have names of people and the dates in which they were bought written in it. Is it permissible for me to take some of them as, after all, no people will benefit from them since these books are specialist classical books?
Answer

It is not permissible for you to take these books or handle them. This is because the owner of the books is known. The name is written in the books and therefore, the owner must be sought out. It may be that he has forgotten his books or misplaced them. The owner of the book needs to be found and the books returned to him. If he has left the books at the mosque for people to read them, those books are left as an endowment for that mosque and it is not permissible to remove them. In any case, it is not permissible for you to take any of those books. This is because the owner is known, and even if he was not known, it is most likely that these books were left as a charitable endowment for the mosque. In case of the latter, it is not permissible to take it out of the mosque except when there is a manifest benefit in doing so in which case it can be taken from one mosque to another. This happens quite often. For instance, students who attend classes at mosque sometimes have an emergency or have to use the toilet and they need to rush and leave at once, catching a ride or walking, and consequently forgetting their books. In such a case, especially when the person has his name written in the book and he is a student who is known in that mosque, and therefore the books have an owner and are not lost. Thus, it is not permissible to handle them without the owner’s consent. Effort must be made to find him and the books are to be left at a safe place until he returns to collect them. As for benefiting from these books at the mosque, then knowledge is public property and the harm of using them is negligible and therefore, some leeway can be made. However, the default ruling is that using someone else’s property is not permissible without their permission. If these books were gifted to the mosque, taking them out is not permissible. Hence, if it were gifted for a particular place then that must be honored, except if there is a manifest reason, such as no one would read these books there so they are taken to another mosque where people would read them.