I must share it, there are many useful resource

http://blogs.msdn.com/b/mssmallbiz/archive/2013/06/18/huge-collection-of-free-microsoft-ebooks-for-you-including-office-office-365-sharepoint-sql-server-system-center-visual-studio-web-development-windows-windows-azure-and-windows-server.aspx?Redirected=true

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

Thank you , Eric