IROAI

An Introduction to Information Retrieval (PDF)
A Project Guide to UX Design by Russ Unger & Carolyn Chandler
About Face 3 by Alan Cooper, Robert Reimann, & David Cronin
Ambient Findability by Peter Morville
Card Sorting: Designing Usable Categories by Donna Spencer
Communicating Design by Dan Brown
Defensive Design for the Web by Matthew Linderman & Jason Fried
Designing for Interaction by Dan Saffer
Designing for the Social Web by Joshua Porter
Designing Gestural Interfaces by Dan Saffer
Designing Interfaces by Jenifer Tidwell
Designing Visual Interfaces by Kevin Mullet
Designing Web Navigation by James Kalbach
Designing Web Usability by Jakob Nielsen
Don’t Make Me Think by Steve Krug
Emotional Design: Why We Love (or Hate) Everyday Things by Don Norman
Everyware: the dawning age of ubiquitous computing by Adam Greenfield
Handbook of Usability Testing by Jeffrey Rubin & Dana Chisnell
Information Anxiety 2 by Richard S. Wurman
Information Architecture: Blueprints for the Web by Christina Wodtke & Austin Govella
Information Architecture for the World Wide Web by Louis Rosenfeld & Peter Morville
Mental Models: aligning design strategy with human behavior by Indi Young
Observing the User Experience by Mike Kuniavsky
A Practical Guide to Information Architecture by Donna Spencer
Practical Information Architecture by Eric L. Reiss
Sketching User Experiences by Bill Buxton
Subject To Change by Peter Merholz, Todd Wilkens, Brandon Schauer, & David Verba
Tagging: people-powered metadata for the social web by Gene Smith
The Design of Everyday Things by Don Norman
The Elements of User Experience by Jesse James Garrett
The Inmates Are Running the Asylum by Alan Cooper
Thoughts on Interaction Design by Jon Kolko
Usability Engineering by Jakob Nielsen
Web Form Design by Luke Wroblewski
Web Redesign 2.0: workflow that works by Kelly Goto & Emily Cotler
Women, Fire, and Dangerous Things by George Lakoff

The UX Book Index from Rosenfeld Media.
A list of service design books from @SDNetwork