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.
https://blogs.msdn.microsoft.com/mssmallbiz/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/

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.
https://blogs.msdn.microsoft.com/mssmallbiz/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/