Craig S. Mullins: "Database Administration - The Complete Guide to DBA Practices and Procedures", 2nd Edition
(2012, Addison Wesley)
C.J. Date: "An Introduction to Database Systems", 8th Edition
C.J. Date: "Database in Depth: Relational Theory for Practitioners"
C.J. Date: "The Database Relational Model: A Retrospective Review and Analysis: A Retrospective Review and Analysis"
Joe Celko: "Thinking in Sets"
"Applied Mathematics for Database Professionals"
Joe Celko: "SQL Programming Style"
John L. Hennessy, David A. Patterson: "Computer Architecture"
About SAN, disks, memory, CPU etc.
Tapio Lahdenmaki et al: "Relational Database Index Design and the Optimizers"
Bill Karvin: "SQL Antipatterns"
Mana Takahashi: "The Manga Guide to Databases"
(No Starch Press)
DevelopmentSteve McConnell: Code Complete, 2nd Edition
(2004, Microsoft Press)
This book is actually written for developers, but contain so many gold nuggets for Database Administrators. Personally I think the book should be mandatory reading - several times - to anybody working with IT development.
Jeffrey E. F. Friedl: "Mastering Regular Expressions", 2nd Edition
Deep book on regular expressions. Covers several environments and programming languages. Very good.
Eric T. Freeman et al: "Head First Design Patterns"
Microsoft WIN32 Developer’s Reference Library
The Win32 technology is by many seen as obsolete with .NET, but still there are many Win32 components inside and around SQL Server.
COM+ Developer’s Reference Library
There is still a lot of COM, COM+ and DCOM in and around SQL Server. This book is highly relevant to the experienced System-DBA.
Operating SystemHewardt, Mario: "Advanced Windows Debugging: Developing and Administering Reliable, Robust, and Secure Software"
Mark Minasi et al: "Mastering Windows Server 2012 R2"
William R. Stanek: "Inside Out - Windows Server 2012 R2 Configuration, Storage, & Essentials"
DevOpsThis section is added as I as a (Database) Administrator often is involved in method discussions. Recently more and more on the DevOps terms.
Gene Kim, Kevin Behr, George Spafford: "The Phoenix Project"
(IT Revolution Press)
Jez Humble, Davis Farley: "Continous Delivery"