After five long years of arduous development, the official industry standard Epub reading app has finally been released as a desktop app.
Initially released in February 2012, Readium was supposed to become the core component for all third-party ebook apps. Alas, it took so long to develop Readium that by the time it was ready for public use, most developers had come up with their own simpler solutions. And according to a couple developers I know, the Readium code was so complex and proved so difficult to check for errors when compiled that it wasn't worth the hassle.
As a result, over the course of 5 years Readium had only been officially released as a Chrome web app. (Bluefire, the ebook developers who wrote most of the Readium code, also used Readium in their Cloudshelf app.)
But now, thanks to EDR Lab, an alpha version of Readium for Windows, Linux, and macOS has been released:
One year ago, the European Digital Reading Lab started working on an important missing piece in the set of reading systems developed by Readium: a desktop application. Students use intensively their PC or Mac to access textbooks; visually impaired people commonly use a PC with a “screen reader” application to access any type of publication; and more generically, many ebook readers in public libraries, at work or at home, would like to access EPUB files on there desktop computer. But there was no good open-source EPUB reading application for them.
With the financial help of EDRLab founding members, and especially the help of the French CNL (Centre National du Livre), we started prototyping around a new kind of reading app, which could be deployed on the three main desktop operating systems, i.e Windows 10, MacOS and Linux.
The source-code of this application would be given to the Readium Foundation with a liberal license, so that everybody can customize the application for its specific usages.
You can download the apps on GitHub.
I have tried it. It is very much an alpha release.