Bob Shaw 
Fugitive Worlds [EPUB ebook] 
Land and Overland Book 3

The opening of The Fugitive Worlds finds Toller Maraquine II – grandson of the hero of The Ragged Astronauts and The Wooden Spaceships – bemoaning the fact that life on the twin planets of Land and Overland has become dull and uneventful compared to the stirring times in which his illustrious forebear lived. Then, while on a balloon flight between the worlds, he makes an astonishing discovery – a rapidly growing crystal disc, many miles across, is creating a barrier between Land and Overland. Precipitated for personal reasons into investigating the enigmatic disc, Toller – armed with only his sword and boundless courage – becomes a pivotal figure in events which will decide the future of entire planets and their civilizations.