THE DUKE Leto Atreides leaned against a parapet of the landing control tower outside Arrakeen. The night's first moon, an oblate silver coin, hung well above the southern horizon. Beneath it, the jagged cliffs of the Shield Wall shone like parched icing through a dust haze. To his left, the lights of Arrakeen glowed in the haze--yellow . . . white . . . blue.