Huge collection of Microsoft technical EBooks
This amount of knowledge needs at least one blog ticket 🙂
Many PDF (also epub and mobi format) around technical subjects like Office 365, Windows Server 2012, SQL Server, Sharepoint, SQl Server, System Center, Visual Studio, … are available as free download on Microsoft website :
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
Feel free to download, learn and progress !