Here are some recommended User Experience Books.
Don't Make Me Think: A Common Sense Approach to Web Usability (Voices That Matter) Steve Krug
This is an updated version of the original book that I used to buy in bulk to ease the progress of UX projects. It is a great way to turn clients into user advocates.
Rocket Surgery Made Easy: The Do-it-yourself Guide to Finding and Fixing Usability Problems Steve Krug
Another great book by Steve Krug. This book provides a great introduction to user research and user testing. It puts the user back into user experience.
The Design of Everyday Things Don Norman
This book inspired the creation of Google and has been a corner stone for approaching user centered design problems.
The Inmates Are Running the Asylum (2nd Edition) Alan Cooper
This is a polemic against the issues with technical lead software developement. The issues in this book still ring true today.
About Face: The Essentials of Interaction Design
This is the forth edition of this seminal book on interaction design, a key part of user experience.
Information Architecture: For the Web and Beyond Peter Morville, Louis Rosenfeld and Jorge Arango
The 'polar bear book' has remained the original and best book on information architecture, a vital part of creating meaning for experiences. Once this was just about websites and now with this new fourth edition the book expands to other platforms.
100 Things Every Designer Needs to Know About People: What Makes Them Tick? (Voices That Matter) Susan Weinschenk
Often with an experience we want to convince and persude users. Reasearch can provide answers about what the user wants and needs, but then how can we expand on this. Here are a 100 extra tools to use.
Other books with reviews.
Lean UX by Jeff Gothelf and Josh Seiden
System Thinking by Donella Meadows