I deliberately limited myself to at most four resources in each category, so some great resources are not included.
Overview of this page
Introduction to usability and user experience
Steve Krug (2013). Don’t make me think. Third edition. New Riders.
The website of the Nielsen Norman Group. Free.
Hugh Beyer & Karen Holtzblatt. (1998). Contextual design—Defining Customer-Centered Systems. Morgan Kaufmann.
Steve Portigal. (2013). Interviewing Users: How to Uncover Compelling Insights. Rosenfeld Media.
Joe Dumas & Beth Loring (2008). Moderating usability tests: Principles & practices for interacting. Burlington, MA: Morgan Kaufmann.
Joe Dumas & Ginny Redish (1999). A practical guide to usability testing (Revised edition). Exeter, UK: Intellect.
Carol Barnum. Usability testing essentials: Ready, Set …Test! Second edition. Morgan Kaufmann.
Tom Tullis & Bill Albert. (2013). Measuring the user experience: Collecting, analyzing, and presenting usability metrics (Second Edition). Waltham, MA: Morgan Kaufmann.
The calculators on Jeff Sauro’s website. Free
Steffen Weichert & Gesine Quint & Torsten Bartel. (2018). Quick Guide, UX Management (in German). Springer Gabler.
More resources on the UX maturity page.