The Kindle for PC application was designed to be a free tool that lets you read Kindle books on your PC-no Kindle required. If you already have a Kindle or you use Kindle for iPhone, Amazon's Whispersync functionality automatically synchronizes your last page read so you can easily switch between devices and pick up reading from where you last left off. Whispersync automatically synchronizes your bookmarks and your reading location among devices registered to the same Amazon.com account. When you open a Kindle book you're also reading on another device, you'll have an option to go to the furthest page read if you're further ahead on the other device. This helps you pick up where you left off regardless of which device you're using. Whispersync is automatic and enabled by default. To manually sync when using Kindle for PC, go to the Home screen and click the "Menu" button at the top of the page; then select "Sync and Check for New Items."