calibre is an open source Mac utility for managing your e-books. With its help, you can read and convert your favorite e-books, fetch metadata for any of your electronic books, download the latest news articles, and so much more.
The application works with a wide variety of e-book formats, provides you with a feature-rich editor, and helps you find and download e-books from the web. You can also use this program to keep track of the latest news. Simply subscribe to a RSS feed and the app will automatically download the news to your Mac.
Another advantage is the fact that the utility comes with an efficient e-book converter. This built-in tool works fast, preserves the quality of the original files, and is very simple to handle.
Personally, I'm not a big fan of this app's design. It's not as intuitive as other Mac applications, with dozens of screens each with a certain amount of panels. You might need to waste a while to find the app panel or the setting you need. Not to mention, the application doesn't bring you a built-in help manual. So, if it's the first time you work with this type of utility, you should first check the app's homepage and read the instructions before using this program on your Mac.
Still, this application comes without a price and might prove to be of good use if you work with e-books often.