Springer-Verlag just published a new book on usability entitled "Maturing Usability Quality in Software, Interaction, and Value". It consists of a collection of essays on usability work, focusing on agile software development, model-based evaluation, remote usabilty, and much more. More detailed information can be found here.
The book also contains a chapter authored by me on idea generation. The abstract reads: "This chapter discusses how to understand the purpose of formative usability evaluation. We raise concerns about common ways of understanding usability evaluation, and propose a complementary view of usability evaluation as idea generation. Implications of this view for researchers and practitioners are discussed, and it is argued that seeing usability evaluation as idea generation may help move research in evaluation methods forward. In addition, we suggest practitioners some benefits of viewing their work as idea generation and some concrete techniques based on this view."