Water, Mars, and Science Fiction
Kim Stanley Robinson has a nice essay in the New York Times Book Review outlining the history of science fictional engagements with Mars (including his own), and specifically the role that the possible presence or absence of water has played in it.
Mars and science fiction came of age together in the 1890's, and ever since they have had a tight relationship, a feedback loop that has made both famous . . .
Essay: A Red Planet Forever in the Orbit of Science and Dreams (via boingboing)