The Kindle Paperwhite succeeds Amazon's Kindle Touch, which also employed a touchscreen. In fact, the home screen and general interface layout of the two devices are quite similar.
As a touch-based e-book reader, the Paperwhite naturally lacks physical buttons. Instead, Amazon employs a user interface that it calls EasyReach, which relies on defined zones for menu access and turning pages.
It's easy enough to access the menu and toolbar; simply tap the top of the screen. To flip to the next page, tap the lower-right half of the screen. Likewise, tap the leftmost edge to go back to the previous page. To take a screenshot, simultaneously tap and hold any two opposite corners of the screen (for example, the top-right and bottom-left, or top-left and bottom-right).
Our only complaint is that EasyReach, in its current form, is optimized for right-handed users. Ideally, we'd like to see an alternative layout for lefties.
If you're not familiar with the Kindle family, models sold with ”Special Offers" do not differ in any significant way from those without. The sleep screen is the only thing that sets them apart. Instead of pictures, Special Offers models display Amazon advertisements. And they’re not just limited to books. Kindles with Special Offers push ads for anything Amazon sells that the company wants to promote, such as a coupon for $30 off a pair of $100 jeans (an actual example). If you don't mind the ads showing up when you're not using your Paperwhite, buying a Special Offers model allows you to secure a lower price.