Accurate records for one heighliner, which bore various names and numbers but which was indisputably a single vessel, cover the period from 4768 to 8287-more than thirty-five hundred years. The earliest known heighliners were constructed some two centuries after the establishment of the Guild monopoly, during the time CHOAM was enjoying its most vigorous expansion. Within another two centuries, at least seventy-five percent of all Guild tonnage was carried in the heighliners. A late, incomplete document, a report dated 253:9920 from the Guild yardmaster at Ix to his superiors, shows that even then the Guild maintained nearly 275,000 smaller vessels for courier, passenger, and miscellaneous travel. But the same report clearly indicates that the total payload of all those minor ships together could not have been more than ten percent of the total payload of the heighliner fleet. The Guild under the Atreides was con- HEIGHLINER strained to devote a large percentage of its transport capacity to military uses, ferrying Fremen, conscripts, and, later, Fish Speakers from one trouble spot to another But even during the jihad years of the Emperor Paul Muad'Dib flie primary ase of the heighJiners was commercial Although they were among the very fasten interstellar vehicles evef built, they were not adaptable to combat uses (They did, Of course, ferry warships, but the Guild was careful to unload far from any contested regioji) The Guild was diligent in protecting its investments, and no heighhner is known to have been lost to military action Few, indeed, seem to have been lost for any reason The Guild navigators did not make mistakes, the Guild maintenance crews were scrupulous and competent But even the best-constructed and best-maintained machines eventually wear out Heighlmers removed from service were apparently seldom broken up, probably because the risks involved in dismantling the neutrino circuitry, which, by its nature remained ' live" for centuries after power to it has been cut, outweighed the modest economies of recycling materials Decommissioned heighhners were parked m cold orbits" around planetless stars (The discovery, about three centuries ago, of one such retirement site at Eta Ophiuchi provided most of our specific information about the heighhners, references to them in the documents of the Rakis archives have proven so far to be surprisingly sketch} and vague) While explanations of the technology be hind heighhners is available elsewhere (see entries HOLTZMAN EFFECT and INTERSTELLAR NAVIGATION, and Further references below), two features of the Guild equipment should be remarked here First, the neutrino circuitry mandated by field mechanics relied much HEIOHLJNER 306 HEIGHL1NER more on sheer power than on the elegant geometries characteristic of modern craft. For this reason a heighlincr was a simple, featureless globe.