From Redgate website you can download (for free) the ebook SQL Server Execution Plans written by Grant Fritchey and technically reviewed by Hugo Kornelis. This ebook can not be miss in your digital library! Enjoy! 

The series of free eBooks ''The SQL Server and .NET Blog eBook Series'' by Artemakis Artemiou (@artemakis) collects dozens of articles explaining how to solve practical problems in these areas: Database DevelopmentDatabase AdministrationPerformance Tuning Developing SQL Server (The SQL Server and .NET eBook Series)This ...

From Red-Gate website you can download (for free) the ebook Performance Tuning with SQL Server Dynamic Management Views written by Louis Davidson (@drsql) and Tim Ford (@sqlagentman). DMVs are objects that publish information about the health state of a SQL Server instance. They allow you to monitor the heart of the system to diagnose ...