Patrick W. (The Contemporary Trends Institute, London, UK) Jordan & Ian Lyall McClelland 
Usability Evaluation In Industry [PDF ebook] 

This book provides a variety of answers in its description and discussion of new, sometimes radical approaches to `usability evaluation”, now an increasingly common business tool. It contains new thinking of the subject of usability evaluation in industry. Contributions come from those involved in the practice of industry-based usability evaluation