In 1999, Andrew Smith was interviewing Charlie Duke, astronaut and moon walker, for the Sunday Times. During the course of the interview, which took place at Duke's Texan home, the telephone rang and Charlie left the room to answer it. When he returned, some twenty minutes later, he seemed visibly upset. It seemed that he'd just heard that, the previous day, one of his fellow moon walkers, the astronaut Pete Conrad, had died. 'Now there's only nine of us,' he said. Only nine. Which meant that, one day not long from now, there would be none, and when that day came, no one on earth would have known the giddy thrill of gazing back at us from the surface of the moon. The thought shocked Andrew Smith, and still does. Moondustis his attempt to understand why.