NASA's free history e-book collection
Why is pdf the default/de facto single-file publication format, even in public domain or copyleft works?It has so many drawbacks: it's usually unparseable; it's usually unsearchable; incompatible with all sorts of format conversions; its rigid pagination makes it cumbersome to read when not in zoomed-in, especially on mobile; its best features require proprietary software when authoring them, yet most people seem to use generic pdf file export; it's been subject to exploits... and the list goes on.