I just finished this superbly written, spellbinding novel. Stephen Baxter's technical background clearly shows and makes this novel so enjoyable for true SCIENCE fiction fans. There is nothing worse than a story involving fantastic "inventions" of new technologies which make no sense at all. Any technologically minded reader will enjoy this book as much as I did, simply because the scenarios are believable and, as we saw from the actual unmanned Mars probe efforts, feasible. The political undercurrent, based partly on actual and partly on fictional events, adds even more factuality. The minute details with which Baxter describes the engineering feats performed by NASA's subcontractors, as well as the many successes and failures prior to the Mars Mission launch itself, emotionally involve the reader in the storyline. The characters are not your glorified hero-types but as close to normal as they can be under the circumstances. The gritty descriptions of the tests and routines ascans have to go through may be objectionable to some "sensitive" minds, but they open up your eyes to the demands placed on the human body during space flight, and do not gloss over the physical and mental strains as many other science fiction books or movies do. Baxter's story fluidly interweaves the characters' past with the present and presents a well-rounded story which made it hard to put the book down.