Calibre Is an All-Purpose, E-Book Swiss Army Knife
Before we go any further, let's get this out of the way: if you own a Kindle and have no intentions of ever purchasing anything from anywhere other than the Kindle store, then you have no need for the Calibre app. (Though, you can use both concurrently.) As for the rest of you, stick around to find out how to get the most out of your e-book collection and e-reader.
Unlike most pieces of e-book software out there, Calibre offers you genuine management over your collection. This doesn't just mean adding, removing and listing, either. You can convert electronic volumes to just about any format you wish and from any format you can find. Whether it's ePub, Mobi, PDF, Lit, LRF or even plain Word docs, Calibre will convert any of these files to a format compatible with and optimized for your particular device. Calibre even gives you complete control over the metadata, such as author, publisher and tags. If you're only reading books purchased from Amazon or Barnes & Noble, this might not seem like a huge deal, but, if you load electronic class readings onto your e-reader, or download texts from Google Books or Project Gutenberg, this can come in quite handy. These files don't have an agreed upon standard for how to format information such as authors or titles. So you might end up with messy multiple entries because one person decided there should be a space between the "H" and "P" in H. P. Lovecraft and one person didn't, or some book titles might not be capitalized.
As great as the collection management tools are (and we appreciate that moving files to our e-readers is painless), Calibre's most prime feature is the ability to automatically download articles from hundreds of news sites and blogs for free. You can look for new articles on-demand from sites like Engadget or Salon, and load them onto your device for later reading. Or, you can schedule Calibre to automatically download and copy each day's news from The New York Times and other sources. And if you don't like the hundreds of pre-selected news sources, Calibre will accept any RSS feed for custom news "recipes." What makes this so attractive is that, despite all of these articles being available online for free, companies like Amazon wish to charge you a fee to read them on your Nook or Kindle. Of course, you'll have to connect to your computer via USB or Wi-Fi to load the content on your reader first.
Calibre doesn't have a built-in e-book store, and won't be able to open DRMed for-pay books (although it should be able to add them to your library and device), but its other features make these minor complaints. The fact that it works flawlessly, regardless of your OS, means it's our top tool for organizing our digital text. Basically, if you have an e-reader and you're open to expanding beyond the Kindle Store, you need Calibre. Go get it now.