Speaking of law, there is a proverb in the west: "The law doesn't care about trivial matters." You don't need to discuss this matter at the legal level. After all, it is a very small matter.

If we must be serious, it is to analyze whether the behavior of the library is legal and appropriate. From the common sense, the library is a public place, and general public goods are not allowed to be stored there. If the library staff find the books left at the scene when cleaning during the closing period, it cannot be said that it is illegal, because the library has no legal obligation, but it may be appropriate.

Besides, you said there was a special place for you to put your books. Did you agree or did the library explicitly provide it? But in either case, the library has been cleaned up by public announcement, which you should know but don't know. The library thinks that books that have not been taken away are abandoned and reasonable, and it is not only legal but also reasonable to deal with them.

Private property is sacred and inviolable, which is good, but if you put it on public occasions, it shows that you are lazy in safeguarding your property rights, or intentionally abandoned it, and you are told that you should take it away instead of taking it away, which makes others think that you have abandoned your property. The responsibility for this lies mainly with you.