A good friend of mine, Mitch Tulloch, has worked with the Windows Server team at Microsoft to develop a 108 page eBook based on the Preview release version of Windows Server 2012 R2. The book will be updated when Windows Server 2012 R2 actually releases later this year. Actually, rumor suggests that R2 will released in a month or so, but we'll see how that works out.

The eBook is available for download here:  Introducing Windows Server 2012 R2 Preview Release