That's why I refused to buy Kindle books as long as I didn't have a good way of adding them DRM-free to my Calibre library. I do buy Kindle books now. What is

That's why I refused to buy Kindle books as long as I didn't have a good way of adding them DRM-free to my Calibre library. I do buy Kindle books now. What is funny is that there are Kindle books on Amazon that you cannot read on your eInk Kindle! For example, https://www.amazon.co.uk/Forcing-London-Mathematical-Society-Student-ebook/dp/B08GGBF2TR/ref=tmm_kin_swatch_0?_encoding=UTF8&qid=&sr= https://www.amazon.co.uk/Forcing-London-Mathematical-Society... has as its format "Print Replica", which I like for math books as they are basically just high-quality PDFs. But you cannot download it to a Kindle Oasis, for example! Funnily, after you remove the DRM, it just becomes a PDF, and you CAN download it to the Kindle Oasis. That's just ridiculous.