What you check out from a library is protected as personal information. What you buy from a bookstore will most likely end up in a database somewhere. Whether physical or digital there will be a record of the purchase. Digital copies are perfectly fine as long as they're stored on your own media in standard formats such as EPUB, without DRM. (For DRM-free ebooks I'd recommend starting here: <https://www.libreture.com/bookshops/>.)

> What you buy from a bookstore will most likely end up in a database somewhere.

Unless you buy in a real bookstore by cash.

The sale will still be recorded, and your visit will be recorded on the security cameras; there is enough information there to associate the purchase with your identity if someone wants to make the effort. This also limits you to buying whatever happens to be in stock—if the store has to order a book for you there will be a record with your name for pickup, even if you pay for it in cash.

Not that your reading habits are really worth investigating. Or trying to hide.

Security cameras do not store their recordings indefinitely. After a few weeks (at most), any record of your visit will be wiped when the cameras record new video that overwrites your face.

> security cameras

Masks for the rescue.

> there is enough information there to associate the purchase with your identity if someone wants to make the effort.

Which information?

> Masks for the rescue.

You can be identified by your gait these days, and even facial recognition has been modified to work even in the presence of (medical) masks. More exotic forms of mask covering the whole face would just make you stand out even more.

> Which information?

They just need to know what time you were in the bookstore making your purchase. From there they can follow the security footage forward or backward until they have enough clues to piece together your identity. If you're a regular at physical bookstores in your area the odds of remaining anonymous in the face of a proper investigation range from slim to none.

It's all probably technically possible, but requires a lot of resources currently. I doubt that bookstores do that on scale, unless you are targeted by a state actor.