It is fairly apparent to me that the crew did not deliberately land on the taxiway - therefore there must be a reason. It seems likely to me that they were a competent, capable and appropriately trained crew who only wanted to do a professional job that day - we should also recognise that taxiway landings and take-off have occurred numerous times over the years. To berate the crew is not the answer - we have to recognise that the human propensity is to err and we have to develop mehanisms to ensure this does not happen over and over. Step One is to realise that it can happen to anyone. Step Two is to get inside the crew's heads to work out what they saw and what led them to the view they were landing on a runway. Step Three is to revise training to ensure that the visual cues used in these numerous incidents are highlighted and trained out. Murphy's Law says, 'If it can happen, it will happen'. My own experience over many years as an airline pilot has borne that out, and therefore I want to understand what happened here rather than be too self-righteous about it.