At a basic level, you can copy and paste it out. CTRL+A, CTRL+C, CTRL+V. Done. You can also use Poppler's PDFtoText https://en.wikipedia.org/wiki/Pdftotext htt

At a basic level, you can copy and paste it out. CTRL+A, CTRL+C, CTRL+V. Done. You can also use Poppler's PDFtoText https://en.wikipedia.org/wiki/Pdftotext https://en.wikipedia.org/wiki/Pdftotext Calibre struggles with some PDFs, especially those that don't contain metadata about chapter headings etc. That's a failing on the PDF, not Calibre.