I am pleased to announce unbook, which solves the DRM-free .{epub, mobi, azw3, ...} ebook reading problem by converting the book to a self-contained HTML file with all the images inlined using data: URIs. You can now just read everything in your browser.

https://unbook.ludios.org https://i.imgur.com/uftndd3.jpg

computer programmer, information collector, archivist-librarian with a few items, puzzle game appreciator; github.com/ivan 

But HTMLZ output was created for editing, not for reading (in 2011: https://mobileread.com/forums/showthread.php?t=128076…). Browsers can't read zipped HTML; I kept extracting .htmlz files and fixing styling issues like the awful `text-align: justify`, all of which unbook now handles. https://i.imgur.com/eeigZJx.jpg

The inlining of images was inspired by SingleFile, which convinced me that long data URIs and large HTML files are generally no problem. The rewriting of image URLs to data: URIs is handled by Cloudflare's very helpful lol-html library: https://github.com/cloudflare/lol-html

unbook 0.7.2 is now fixed for macOS, and all platforms have improved error reporting that is less confusing when e.g. calibre ebook-convert is not found. There are improved install instructions on https://unbook.ludios.org

unbook was created after I repeatedly noticed that I had a better reading experience with Calibre's HTMLZ output in Chrome or iOS Safari than with any ebook reader software. Such programs often have peculiar UX issues which are not always outweighed by whatever benefits they offer.