This blog is being written by Amir Kolsky and Scott Bain, two of the  senior consultants at Net Objectives.  We're trainers, authors, and  consultants, and at present are working on a new book we're calling  "Sustainable Test-Driven Development".
Why write a book on TDD?  The short answer is because our students keep  asking us to.  :)  We've been teaching TDD for a decade now, and we've  been told "you really should write a book" so many times we can hardly  count them.  Also, while there are TDD books out there, we've not found  one that is compatible with our approach, specifically focused on  sustainability in the TDD process.  So, off we go to write it. 
We thought it might be a good idea to flesh out some of our content by  writing blogs, each being essentially the seed of an idea that will  subsequently be developed into a longer, more detailed treatment.  Some  of these blogs will turn into chapters, some will be multiple chapters,  still others will only be sections within a chapter.
We also thought that we might as well make this material available to  others as soon as possible, thus this blog is public.  We hope that some  will benefit from reading our thoughts here, and perhaps even offer us  some comments on what we've written.  We'd be very open to constructive  criticism, and appreciative of any collaborative ideas that may be  offered.
Our goal is to blog approximately weekly.  Hopefully that will go better than such goals tend to. :)