I ran across this offer for a free eBook on Windows Server 2008 R2 and thought it would be of interest.
On the Microsoft Learning website, in the Windows Server 2008 section, Microsoft has made available the eBook “Introducing Windows Server 2008 R2” in .PDF and XPS editions. The eBook is free and the only catch is that you must sign with your Windows Live ID to download.
According to Microsoft Press:
Learn about the features of Windows Server 2008 R2 in the areas of virtualization, management, the web application platform, scalability and reliability, and interoperability with Windows 7. Sign in to download Introducing Windows Server 2008 R2, written by industry experts Charlie Russel and Craig Zacker along with the Windows Server team at Microsoft.

Click here for a free Ebook on Introducing Windows Server 2008 R2.