I chatted for a while with Jeff Patton at xpday in London. Very interesting - and very nice - guy. His keynote presentation was fantastic.
He's currently writing a book and you can read it on-line as he increments (writes) and iterates (rewrites) it. The book is called "Agile Development - Outside In - What you need to know to deliver useful, usable, and valuable software in an Agile environment".
Looks fantastic based on my quick skim.
