The easily-overlooked key words in the title of this book are 'Once Upon a Time'. Because Kate Greene's memoir is doubly redolent of that fairytale opening that puts us in a world that is somewhat removed from reality. First, her book is concerned not (of course) with actually living on Mars, but spending four months in an environment that partially simulated what it would be like to be on Mars (but was actually on Hawaii). And secondly, although there is quite a lot about what happened on that experiment, this is not so much a book about exploring outer space as inner space: it's far more a narrative of how Greene feels the experience affected her than it is a conventional narrative. What it reminded me most of was something that seems (literally) worlds away from a space mission: Down in the Valley , the posthumous set of recollections by Laurie Lee of his early life in Slad, a Cotswolds village, in the 1920s. Lee's book (taken from recordings) is about life in a...