Developer's description:

Calibre is a powerful and easy to use e-book manager. Users say it’s outstanding and a must-have. It’ll allow you to do nearly everything and it takes things a step beyond normal e-book software. It’s also completely free and open source and great for both casual users and computer experts.

Calibre’s user interface is designed to be as simple as possible. Large buttons in the main window take care of most of your needs. The vast number of calibre’s features and options is always clearly displayed under intuitive tabs. Its context menus are neatly sorted, so the things you’re looking for almost find themselves on their own. You’re never more than three clicks away from your goal. It’s the result of years of tweaking calibre’s interface based on users’ feedback. Plus, you can change many aspects of how calibre looks and feels and try one of the three built-in library views to browse your book collection using covers, titles, tags, authors, publishers, etc.

Calibre not only can download all the metadata for an e-book (things like title, author, publisher, ISBN, tags, cover or summary) but will also allow you to edit or create metadata in existing or new fields. That way you can track which books you’ve read and which ones you liked. You can also take advantage of the advanced search and sorting functions that use tags, authors, comments and more. You will find the book you were looking for in seconds!

Calibre supports almost every single e-Reader and is compatible with more devices with every update. You can transfer your e-books from one device to another in seconds, wirelessly or with a cable. And you don’t need any additional tools to do that. calibre will send the best file format for your device converting it if needed, automatically.

No matter what PC, laptop or tablet you use, calibre’s got you covered. And if you’re traveling and don’t have your device with you – you can take calibre on a USB stick and use it wherever you are.

Calibre can convert dozens of file types. No matter where you got your e-book from, it’ll be ready for your device in no time. When converting, you can also automatically change the book’s style, create a table of contents or improve punctuation and margins. calibre will also detect the format that’s best suited for your device on its own, so you don’t have to bother.

Calibre can also turn your personal documents to e-books or create them from scratch. It can also take all the mundane things that go with it off your plate. It has automatic style helpers and scripts generating the book’s structure. You focus on the content, calibre will take care of the rest.

Comprehensive e-book viewer:
calibre has a built-in e-book viewer that can display all the major e-book formats. It has full support for Table of Contents, bookmarks, CSS, a reference mode, printing, searching, copying, multi-page view, embedded fonts, and on and on…

Download news/magazines from the web:
calibre can make sure you know what’s happening and automatically deliver stories to your device from hundreds of news sources like The Economist, New York Times, New Yorker Magazine, The Guardian, BBC News, National Geographic, CNN, The Wall Street Journal, The Washington Post, The Atlantic, Scientific American, Wired Magazine, The Telegraph, Forbes, Ars Technica…
You can also teach calibre to deliver news from completely different sites or take advantage of any RSS feed. No searching, no waiting, no hassle.