Rocket man, I think it's going to be a long, long time. When Princeton physicist Gerard K. O'Neill published the first edition of High Frontier back in the mid-70s (just four years after "Rocket Man," to be exact), he just assumed that some of us would be living in orbit by now. Or as the Space Studies Institute's George Friedman puts it in a new essay for this third edition of O'Neill's pioneering work, the L5 society's slogan "L5 in '95!" certainly wasn't referring to 2095. In High Frontier, O'Neill had mapped out a straightforward, manifestly doable path to putting humans into space permanently and sustainably, using 1970s material and current-day Zubrin-style know-how. But O'Neill died in 1992 seeing humanity no closer to fulfilling his bold vision. Freeman Dyson points out in a new introduction to this edition that in many ways we've actually backslided, that the International Space Station (and the current role of NASA) is "not a step forward on the road to the High Frontier. It's a big step backward, a setback that will take decades to overcome." But O'Neill's idea of pursuing an inexhaustible energy supply (solar power in space) and endless room to expand remains tantalisingly attractive. The science has only gotten easier, and the moral imperative has only become more pronounced, with the planet's resources ever-steadily squeezed and the recent knowledge that a mass-extinction event on Earth is nearly inevitable. (O'Neill calls the High Frontier the only chance to make human life--perhaps all life in the universe--"unkillable.") The High Frontier is as exciting a read as it ever was, and six new chapters provide context for the advances made in the 25 years since O'Neill's original manifesto. But perhaps the best addition to this printing is the chance to see and hear the soft-spoken physicist himself, in more than an hour of MPEG video included on the CD-ROM. --Paul Hughes