While Agile Manifesto states “working software over comprehensive documentation”, you can notice that it doesn’t completely rule out the need for documentation. It emphasis on ‘working software’ as the primary objective and ‘comprehensive documentation’, as a secondary one and certainly not a needless one.
Agile or waterfall, good concise documentation , whether customer facing user manuals or installation guides or specification requirement documentations for developers and analysts, helps software users big time in these challenging times. However, many developers consider documentation as second to the last step in the project life cycle. The truth is no one wants to write it or about it and consider it a futile effort that gets in the way of the real work. Many future problems can simply be averted if documentations are given their due.
Discussed detailly here http://bit.ly/2GAmq5d