In 1996, David McKay and his coworkers at NASA's Johnson Space Center claimed that they had evidence of life on Mars and that Martian meteorite ALH84001 was once inhabited, on Mars, by bacteria-like creatures [McKay et al, 1996].Much of the public and the media accepted their claims, but most scientists were deeply skeptical. Now more than 2 years later, what has become of the Martian microbes? Are they appealing illusions, like Lowell's canals on Mars, or are they real? In the time since the paper by McKay and his colleagues was published, the Pathfinder and Mars Global Surveyor spacecraft have revealed volumes about Mars, and an intense lab study has discovered more secrets of the Martian meteorites, but no agreement has appeared on whether meteorite ALH84001 was ever graced by Martian life.