By Master Mavrino: 

The man comes into existence with a certain brain quality, which is in an unprocessed rough form.

The man develops and changes his brain into a data library.
The first stage is the one of unprocessed mass, where he makes drawers to deposit information.

Later on, he transforms this first stage in a better-performing one, which has the form of golden sand. The man writes on this sand and develops.

After his having attained a certain development, the sand is changed for leafs to be placed in the drawers.

By and by, the man stores in the drawers, papyrus; then, sheets of paper.

Afterwards, regular CDs.

The next stage consists in platinum CDs.

The human library passes to a new stage, subsequently, that is, microchips.

And then later, the human library is completed, to wit the chips turn into crystal chip – this is the last stage.