Stephan Schmidt writes
Agile is mostly driven driven by managment and consultants, seldom bottom up by developers.
I found this very odd, and completely contrary to my own experience. From the perspective of someone who first encountered agile approaches in the form of Extreme Programming the problem is almost always how to explain the obvious developer benefits in ways which management will understand.
This phrasing of agile for managers seems to be the purpose of Scrum. I tend to recommend that puzzled managers read up on Scrum, but puzzled developers start with XP and Test Driven Development, which provide some much more tangible developer advantages.