"His treatment of Mars in this book [Man's Place in the Universe] was brief, and in 1907, Wallace returned to the subject with a book Is Mars Habitable? to criticise the claims made by Percival Lowell that there were Martian canals built by intelligent beings. Wallace did months of research, consulted various experts, and produced his own scientific analysis of the Martian climate and atmospheric conditions. Among other things, Wallace pointed out that spectroscopic analysis had shown no signs of water vapour in the Martian atmosphere, that Lowell's analysis of Mars's climate was seriously flawed and badly overestimated the surface temperature, and that low atmospheric pressure would make liquid water, let alone a planet-girding irrigation system, impossible. Richard Milner comments: "It was the brilliant and eccentric evolutionist Alfred Russel Wallace ... who effectively debunked Lowell's illusionary network of Martian canals."Wallace originally became interested in the topic because his anthropocentric philosophy inclined him to believe that man would likely be unique in the universe (Wikpedia article on Alfred Russel Wallace, accessed 02-2017).