How do you think I should assemble this?

I just had an idea. Let me explain that most of my furniture takes up my room, so I don't have any for an actual bookshelf. But wait for it, I thought of taking a big box and then using lids from shoeboxes as the shelves to make myself a bookshelf. Only problem: What should I use to stabilize the lids with? At first, I thought of nails but then I realized those might hurt the books when I shelf them & no book lover wants that. So, what do you think I should use if I plan to carry this idea of mine out? How should I attach the lids without any cause of harm to the books once I shelf them?

How do you think I should assemble this?
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