See "Agile Documentation" - a paper by by ScottAmbler, Copyright 2001, at http://www.agilemodeling.com/essays/agileDocumentation.htm
(A question of AppropriateTechnicalDocumentation, perhaps?)
This is a Very Good Article. Scott makes the important point that the decision on how much to invest in documentation is a decision that the stakeholder should make. Letting the decision be make for you either by historical momentum or the dictates of a process can be suboptimal for a project. -- DaveSmith
Very nice article.
A thought I had while reading the "4. When Does a Model Become Permanent?" section:
But also keep in mind that the value of documentation includes the cost savings that accrue to you during the time you have it. So documentation that helps you understand user requirements or more effectively develop the software will be more valuable if developed sooner (and its value goes down the longer you defer creating it).
"Agile Documentation" is also the title of a book by Andreas Rueping - see my review at http://cplusplus.anthonyw.cjb.net/agile_documentation_review.html -- AnthonyWilliams
ISBN 0470856173