I haven't used Calibre GUI but have many times used its tool ebook-convert. Really very useful. https://manual.calibre-ebook.com/generated/en/ebook-convert.ht

I haven't used Calibre GUI but have many times used its tool ebook-convert. Really very useful. https://manual.calibre-ebook.com/generated/en/ebook-convert.html https://manual.calibre-ebook.com/generated/en/ebook-convert....