The Good: Kindle for Android offers a number of visual customization options, Shelfari integration, a built-in dictionary, and other extras. You can use the Send to Kindle feature as an Instapaper-like tool for saving items from around the Web. The Bad: Credit card is required even for free downloads. Doesn't let you name bookmarks. The Bottom Line: With convenient features like Send to Kindle and Shelfari integration, Kindle for Android is a rock-solid e-reader app, especially for anyone already invested in the Amazon ecosystem. The free Kindle app for Android is an excellent e-reader app that seamlessly ties to your Amazon account. It does a good job of presenting e-books, can easily reach into Amazon's enormous library of downloadable works, and comes with a few bells and whistles to enhance your overall mobile reading experience.Overview The app opens up to the Home screen, which has lists of best sellers, editors' picks, and popular sample books available for browsing. In addition, the Home screen displays the books that are tied to your Amazon account, all neatly organized in a 3D carousel interface. From here, you can either tap a book to go inside or long-press to pull up more options, like going to the beginning of the book, going to the last page read, or removing it from device. The long-press menu also gives you a nifty option to pull up Book Extras provided by Shelfari. Book Extras are community-curated factoids (think Wikipedia) that are meant to provide readers with helpful information as they read. Meanwhile, the rest of the app's controls are tucked into a sliding menu off to the left. If you want to expand your library, the Kindle Store is a tap away from the Home screen. In the store, you'll find Amazon's catalog of books, magazines, and newspapers. Additionally, the Kindle app can handle illustrated children's books, comics, and graphic novels. And if you're not quite ready to commit to a purchase, Kindle lets you preview the first chapter of any book before buying.One thing I don't like about the experience is that Amazon requires credit card information even if you're downloading free e-books. While you read Kindle's in-book experience is as straightforward as it gets. To turn the page, simply swipe or tap somewhere in the margin. A tap to the center of the page brings up a status bar with location information and reader controls. There's also a menu at the top of your screen, in case you want to change text size, brightness, margins, line spacing, or background color. For now, the Kindle app offers only black, white, and sepia (my favorite) background options, but hopefully Amazon will add other textures and colors in the future.