How can you put lots of ePub books at the same time to a give e-reader app?
 

In bulk, instead of downloading one by one from Dropbox like I have been doing?

Most reading apps will allow you to open books from a specified folder on the device, so just copy your books into the appropriate folder.

That's what I tried to do but it doesn't show when I open the app.

When I open the folder I see the ePub files that I have downloaded from Dropbox are in a folder of its own, while when I copy the ePub straight from the computer it doesn't have a folder of its own.

Which reading app are you using?

ridibooks.

Perhaps it's an issue with the app? I use Moon+ Pro and that can open books stored in any folder on the device.

I have a folder on all of my devices called my ebooks. I simply connect my devices to my pc and highlight all my books and drop them into the folder.

Once that is done, I go to my device, open Moon+ Pro and tell it to import all my books from my ebooks folder. Considering I have over 1300 books it takes a while, but once done there are all of my books.

What I love about Moon+ Pro is that whenever I add books into the folder, it will automatically scan the folder and import the new books.

Calibre Companion is one way to add in bulk or you can use the LAN feature of ES File Explorer and copy them over to your device. I don't like using USB cables if I don't have to. For bulk downloading from Dropbox, ES File Explorer has that feature too.

I love the auto important feature too.

I usually use dropbox..

That's cool, I don't trust anyone's cloud, I like to keep my books in my sole custody at all times.