It works well to open files from a web link (HTTP://...). However, if I try to open local files (local hard drive or local network), I get endless "open with..." dialogs.
I found a dirty fix : when I open a file from the web, the address always starts with "moz-extension://697be157-ddf5-4bbd-bd58-56b42dd47af5/reader.html", so I bookmarked this address, and it launches a "blank" epubreader interface, from there I can click the top gray "open" menu, so I can browse my local computer manually. It would be a lot nicer if I could just double-click files from Windows Explorer.

It would be nice to make use of the speech synthesizer capacities to read the book out loud with speed controls

проблема с кодировками текста

Lesen am PC ist sehr mühsam damit / Reading on PC is not easy

The earlier version is lovely - the lack of obvious links in the main page is a problem, the links to working versions may be there and it's possible I haven't seen them but this is part of the definition of 'no OBVIOUS' links! No add-on developer should be collaborating in this desire to herd the sheeple into auto-update braindeath, "Automatically update" == "oh yes master developer I trust you to run anything you like on my system anytime you feel like it" Or, in my case NOT.

Your earlier version is lovely, you should be making it obviously available and telling people that Firefox 52 ESR is perfectly functional, with none of the RUSTbucket crippling the Chrome-Crazy development team want to inflict!

All the good add-ons work ok on Firefox 52, if you get 52.2.0 then you may need to alter about:config to force it not to complain about version numbers (do a websearch!) but otherwise it's equally lovely.

An epub library interface is necessary!
For example, now i've to search the ebook in a directory full of other titles whenever is necessary to open it again. It's a little disgrace.
My solution:
- Install Firefox ESR 52.0 portable
- Install EPUBReader version 1.5.0.12
VOILÀ! Back to practicality.

界面太丑了

It used to be a great add-on till they changed it all.
Now you don't have a visible index on the left side like you used to have, you can't just switch to another chapter that easy anymore or see where you are at, you need to to go to the index button first to make the index visible and if you want to further read your last page you have to close the index again. It is not possible to see the index and the page you want to read simultaneously. A sidebar would be way better than an autohide bar or at least the choice between those two and not just the autohide bar this add-on has now. I also can't just click on a epub download and it opens automatically in the epubreader, instead I have to save it, go to firefox open the epubreader and then search for my book which is really annoying and not user friendly.
The older version is great and much more usable, this new one has too much flaws.

no search option

Das Add-On ansich ist ganz gut. Das UI ist sehr altbacken, funktioniert aber.

Allein die Möglichkeit, die wohl einem Firefox Update zum fiel, ePubs direkt aus Windows oder einem Download zu öffnen fehlt inzwischen. Dadurch ist der Nutzen des Add-Ons leider kaum noch gegeben, da ist es sinnvoller extra Software zu installieren.

эх блин все ссылки в книге сплошным цветом, не годится

This is not a bad addon. It reads EPUB files like it says it does. But compared to the old addon, it has some issues caused by the new Firefox security. There is no longer a catalog of books that one has read in the past, so one can go back and continue reading that book. The Epubreader icon is only in the toolbar, and is no longer on the Tools menu of Firefox. I can't find any link to the Github project, I'm not sure it even has a Github project. There is no link in the toolbar icon to take one to the Mozilla addon page, the support page at http://www.epubread.com, or the Github page to enter issues.

I've read several EPUB books so far with no issues. It just needs a bit more polish as the author had to start over and rewrite this for Firefox 54.

When I make the Firefox window short and thin, then I can't see the bottom lines of the chapter. But this only happens when the FF window is too small. I'm going to have to use a standalone reader software because I can't find an addon that works with my ebooks.

EDIT: There are some EPUBs that are made by Pandoc which EPUBreader has a problem with. The problem is EPUBReader does not show the last few lines of the EPUB chapter if the Firefox window is not wide enough. This problem seems to stem from any EPUBs made by Pandoc.

The new version... hmm... catalogue has gone, or has been hidden well. So instead of the ease with epub I now - well until I downgraded - have to browse around hoping to find what I am looking for. Why did that go?
Besides the new layout.. hmm... maybe fine if you read a book from one end to another, but not great for anything but that.

...and that is the interface.
Having read the instructions on the author's website I failed to open an EPUB document which I had in a folder. After reading some of the reviews and making several attempts I managed to read the book.
I would have liked to be able to reopen the book and carry on reading without having to set a bookmark.

It is evident that Firefox users are unhappy with the Add-on updates needed for the upcoming new requirements.
It would be helpful if there was a mozillaZine Forum for this Add-on so that users and the author could interact publicly.