Microsoft have provided free books for reference on the following -
Microsoft Office
Deployment guide for Office 2013 Preview
First Look: Microsoft Office 2010
Microsoft Office 365: Connect and Collaborate Virtually Anywhere, Anytime
Microsoft Office 365 for professionals and small businesses: Help and How To
Security and Privacy for Microsoft Office 2010 Users
Share Point
Deployment guide for SharePoint 2013 Preview
Create a Balanced Scorecard
Configure Kerberos Authentication for SharePoint 2010 Products
SharePoint Server for Business Intelligence
Get started with SharePoint Server 2010
Deployment guide for SharePoint Server 2010
Upgrading to SharePoint Server 2010
Profile synchronization guide for SharePoint Server 2010
Remote BLOB storage for Microsoft SharePoint Server 2010
Governance guide for Microsoft SharePoint Server 2010
Business continuity management for SharePoint Server 2010
Technical reference for Microsoft SharePoint Server 2010
SQL Server
Books Online: Backup and Restore of SQL Server Databases
Books Online: Data Analysis Expressions (DAX) Reference
Books Online: Data Quality Services
Books Online: Master Data Services
Books Online: Monitor and Tune for Performance
Books Online: Multidimensional Expressions (MDX) Reference
Books Online: SQL Server Distributed Replay
Books Online: Transact-SQL Data Definition Language (DDL) Reference
Books Online: Transact-SQL Data Manipulation Language (DML) Reference
Introducing Microsoft SQL Server 2008 R2
Introducing Microsoft SQL Server 2012
Master Data Services Capacity Guidelines
Microsoft SQL Server AlwaysOn Solutions Guide for High Availability and Disaster Recovery
Microsoft SQL Server Analysis Services Multidimensional Performance and Operations Guide
QuickStart: Learn DAX Basics in 30 Minutes
SQL Server 2012 Tutorials: Analysis Services - Data Mining
SQL Server 2012 Tutorials: Analysis Services - Multidimensional Modeling
SQL Server 2012 Tutorials: Analysis Services - Tabular Modeling
SQL Server 2012 Tutorials: Reporting Services
SQL Server 2012 Tutorials: Writing Transact-SQL Statements
SQL Server 2012 Upgrade Technical Guide
Visual Studio
Moving to Microsoft Visual Studio 2010
Web Development
Deploying an ASP.NET Web Application to a Hosting Provider using Visual Studio
Developing Modern Mobile Web Apps
The Entity Framework 4.0 and ASP.NET Web Forms – Getting Started
Getting Started with ASP.NET 4.5 Web Forms (Beta)
Getting Started with the Entity Framework 4.1 using ASP.NET MVC
Intro to ASP.NET MVC 4 with Visual Studio (Beta)
Introducing ASP.NET Web Pages 2
Windows
Deploying Windows 7: Essential Guidance
Programming Windows 8 Apps with HTML, CSS, and JavaScript (First Preview)
Windows Azure
Autoscaling Application Block and Transient Fault Handling Application Block Reference
Building Hybrid Applications in the Cloud on Windows Azure
Create Your First Application - Node.js and Windows Azure
Drupal on Windows Azure
Migrating Data-Centric Applications to Windows Azure
Moving Applications to the Cloud, 2nd Edition
Windows Azure Prescriptive Guidance
Windows Azure Service Bus Reference
Windows Phone
Developing an Advanced Windows Phone 7.5 App that Connects to the Cloud
Programming Windows Phone 7
Windows Server
Introducing Windows Server 2008 R2
Introducing Windows Server 2012 (Based on Beta)
Understanding Microsoft Virtualization Solutions: From the Desktop to the Datacenter, Second Edition
Career
Own Your Future: Update Your Skills with Resources and Career Ideas from Microsoft
LINK -
http://social.technet.microsoft.com/wiki/contents/articles/11608.e-book-gallery-for-microsoft-technologies.aspx
