In 1969, in his first book, Chariots of the Gods?, Erich von Däniken cited the absence of corrosion on the Delhi pillar and the unknown nature of its creation as evidence of extraterrestrial visitation.[42][43] When informed by an interviewer, in 1974, that the column was not in fact rust-free, and that its method of construction was well-understood, von Däniken responded that he no longer considered the pillar or its creation to be a mystery.[44][45]Balasubramaniam states that the pillar is "a living testimony to the skill of metallurgists of ancient India". An interview with Balasubramaniam and his work can be seen in the 2005 article by the writer and editor Matthew Veazey.[46] Further research published in 2009 showed that corrosion has developed evenly over the surface of the pillar.[47]