“Flatpak App of the Week” Foliate; A powerful open source and modern ebook viewer built for GNU/Linux distributions by John Factotum.
Foliate is a good ebook viewing/reading software written in GTK with lots of cool features. Its interface may seem simple, but don't be fooled by it because Foliate goes beyond reading e-books with its many options and cool tools.

Interface and reading modes
Foliate's interface has two main views, Library and Catalogs. In the catalogs section you can browse and download free and free e-books from known sources. In the library section, you can see every book you download with the application or every book you open manually with reading progress information.
The app offers single-column, double-column or continuous scrolling layouts for reading e-books, right-to-left-reading (RTL) and vertical writing, automatic hyphenation, as well as emulating in look and feel of an e-book reader with an e-ink display. There is also an imitation mode.
Additional Foliate properties
Foliate supports EPUB, Kindle, Mobipocket, FictionBook and also comic book archive formats. The application also supports OPDS feeds if you want to buy your books online.
As just mentioned, there are loads of cool features for all your ebook reading and managing needs. For example, you can search for text or paragraphs in a huge e-book, rotate and zoom images, leave footnotes on layers, turn pages with two finger swipes, or open more than one book at the same time.
The application also includes ToC (contents) menu or sidebar, progress drawer with chapter markers, font adjustment support, line and margin editing, support for adjusting colors and lighting, hiding automatic mouse cursor and reading controls, approximate reading time, bookmarks, and also It offers additional features such as notes that you can export in text, HTML, Markdown or other formats.
Useful tools that Foliate offers for those who want to do more than just read include translation of quotations with Wiktionary, Wikipedia or offline DICT and StarDict dictionaries with Google Translate, text-to-speech support with eSpeak, NG Festival or other TTS engines.
Setup
To install Foliate, first open the Flatpak App Center using these commands. our establishment necessary. Let's do this easily with these commands:
sudo apt-get install flatpak
Our Flatpak App Store is now installed! Now it's time to add repository.
flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
Special for Gnome users!
Gnome users are also recommended to enter the following code!
sudo apt-get install gnome-software-plugin-flatpak
Now that we have installed the Flatpak App Store and added the repository, let's restart our computer. Then we can easily install our application by typing Foliate from the store and pressing install.