Read MOBI Files in Ubuntu 14.04 - A Simple Guide

Reading .mobi Files on Linux with FBReader
If you're a Linux user with .mobi files you wish to read, FBReader provides a solution. This eBook reader program supports .mobi, alongside various other eBook formats, directly within your Linux environment.
Please note that FBReader is designed to work exclusively with non-DRM protected eBook files.
Installation Process
As FBReader isn't available in the Ubuntu Software Center, a manual download and installation are required. Begin by visiting the download URL and obtaining the version compatible with your system – either the 32-bit (x86) or 64-bit (amd64) package.
The libunibreak package is also essential and must be downloaded and installed alongside FBReader. Select the appropriate link for your machine and save both files to a directory within your home folder.
The installation of libunibreak will be performed first. Launch Nautilus (the File Manager) by clicking the Files icon on the Unity bar.
Navigate to the folder where you saved the libunibreak .deb file. Then, double-click the file to initiate the installation process.
The Ubuntu Software Center will open, displaying details for libunibreak. Proceed by clicking the Install button.
An authentication dialog will appear, prompting you for your password. Enter it and click Authenticate to continue.
Upon completion of the installation, close the Ubuntu Software Center window by clicking the X button in the upper-left corner.
To install FBReader, locate the .deb file and double-click it. Follow the same installation steps as those used for libunibreak.
Opening .mobi Files
With FBReader now installed, navigate to a directory containing your .mobi files. Right-click on the desired file and select "Open With Other Application" from the context menu.
A dialog box may indicate that no applications are available. Click "Show Other Applications" to reveal a more comprehensive list.
Select FBReader from the displayed applications and click Select.
The eBook will then open within FBReader. Utilize the on-screen controls to navigate pages or jump to specific locations within the text. To access your entire eBook library, click "Show Library Tree" on the toolbar.
The library view presents a list of authors and books, allowing you to open, remove, and manage eBook information. You can organize your library by author, title, or other criteria.
After successfully opening a .mobi file in FBReader once, subsequent .mobi files can be opened simply by double-clicking them, without needing to manually select the application each time.