In 1960, scientist Freeman Dyson suggested that advanced alien civilizations would rebuild their solar systems into "Dyson spheres" enclosing the sun and harnessing all its output. SF writers developed the idea: Larry Niven's Ringworld (1970) features a cut-down version while Bob Shaw's Orbitsville (1975) broods on the unimaginable vastness of the entire sphere whose inner surface has five billiontimes Earth's land area.Shaw kick-starts his story with panicky intensity as starship commander Garamond, knowing he'll be blamed for the accidental death of his powerful(and unpleasant) employer Elizabeth Lindstrom's young son, goes on the run. He hijacks his own ship and heads for unexplored galactic regions... to discover this gigantic construction. There's a striking scene as he penetrates the single entrance's forcefield:And there--on the edge of a circular lake of stars, suited and armoured to withstand the lethal vacuum of interplanetary space-Garamond had his first look at the green and infinite meadows of Orbitsville.Before long the vengeful Lindstrom catches up, and a spectacularly pyrotechnic escape leaves Garamond's spaceship wrecked 15 million kilometres away from the human beachhead on Orbitsville. That's a tiny fraction of the 300 million kilometre diameter: the sphere's hugeness is emphasised as our hero's team doggedly builds a fleet of planes to be flown in shifts back to base, a journey that'll take three full years. A final nerve-tingling clash gives way to revelations--jolting but in retrospect inevitable--of Orbitsville's hidden purpose. One of the best novels by this popular British author. --David Langford