Here’s two great posts which contains download links to free Microsoft eBooks that are available for SharePoint, Visual Studio, Windows Phone, Windows 8, Office 365, Office 2010, SQL Server 2012, Azure, and more.

http://blogs.msdn.com/b/mssmallbiz/archive/2012/07/27/large-collection-of-free-microsoft-ebooks-for-you-including-sharepoint-visual-studio-windows-phone-windows-8-office-365-office-2010-sql-server-2012-azure-and-more.aspx

http://blogs.msdn.com/b/mssmallbiz/archive/2012/07/30/another-large-collection-of-free-microsoft-ebooks-and-resource-kits-for-you-including-sharepoint-2013-office-2013-office-365-duet-2-0-azure-cloud-windows-phone-lync-dynamics-crm-and-more.aspx