Tammy, I do have a few thoughts on this.
In my view, the “books” that are to be opened represent every person. Each person is a “book”. Today we can all be “read” by other people to a certain extent. As Paul says, “you are our epistle written in our hearts, known and read of all men” (2Cor 3:2).And yet there is much that remains hidden.
But the time will come when the Lord “…will bring to light the hidden things of darkness, and will make manifest the counsels of the hearts…” (1Cor 4:5), or as it is put in another version, He will “…disclose the motives of men’s hearts…” (NASB.) The “books” will be completely open. Every motivation, every thought and impression, will be revealed, and all that will be required of the Redeemed, is that they consider a particular person, and that “book” will be fully opened to their view.