Calibre (`ebook-convert`) makes a decent attempt at converting PDFs to other formats. This of course is very far from perfect, but it takes a good stab at it a

Calibre (`ebook-convert`) makes a decent attempt at converting PDFs to other formats. This of course is very far from perfect, but it takes a good stab at it and I've sometimes found the results to be usable (often with some manual cleanup.) Another example where Caliber compliments Pandoc well is when generating ebooks for sideloading onto kindles. Pandoc can create epubs which Calibre can in turn convert to mobi.