already been tested on the airless satellites of one of the dark stars. Without much interest, Pryor watched Rigel IV fill the screen, gradually become convex. He had landed on far too many worlds to be frightened by the effect of its falling upon him as he neared it. Half-subconsciously, he noted that the star-brakes were working perfectly. He felt the faint jar as the atmosphere engines took over from the star-drive. The little lights on the panel flared and flickered in proper sequence as the flying laboratory began its first circuit of a world that was soon to be blasted to stardust. Later, he realized that he must have dozed off. At any rate, he missed the flicker of green light at the left of the panel and it took the rasping electronic voice that unexpectedly called, “Pilot control, pilot control, pilot control,” to awaken him. He muttered, “_Diamede!_” in sheer disbelief, as he pushed the button that turned off the voice and took over the controls. It couldn’t possibly have happened and yet--the instruments were never wrong. Rigel IV was inhabited--by humans! As he brought the ship in along an ever-slowing parabola, Pryor pulled the outspeaker over in front of his mouth and said, “Lab Able calling _Erebus_, Lab Able calling _Erebus_. Locator shows humanity on Rigel Four, locator shows humanity on Rigel Four. Over.” He held course and watched the seconds tick by on the call chronometer. Eleven, twelve, thirteen ... thirty-five, thirty-six ... A burst of gibberish emerged from the inspeaker until he tuned the unscrambler and heard, “I hear you, Lab Able. Check for inhabitants and arrange immediate evacuation, check for inhabitants and arrange immediate evacuation. Report when assignment complete, report when assignment complete. Time is of the essence, time is of the essence. Over and out, over and out.” Pryor wrestled with temptation. If he put another message through, unscrambled, stating the situation, Interstellar Control monitors would inevitably pick it up. Interstellar Control was death on any interference with inhabited planets. Interstellar Control was already on record as being against the planet-buster test on a usable world. And not even the new chief star marshal was strong enough to buck IC. Pryor smiled and hummed a little Antarean tune as he slowed Lab Able to hovering speed. If he handled the situation adroitly, he should be able to get Marshal Lopez out of the doghouse--and, quite as important, one Echelon Leader Hannibal Pryor back in the big picture. According to the instruments, the humans on Rigel IV lived in a single small settlement in the south temperate zone of the planet, surprisingly close to the forbidding antarctic ice-cap. Pryor cut in distance-detail vision and blinked unbelievingly at a cluster of thatched roofs about a strangely familiar structure with a tall white pointed spire. The fields about the settlement, where they did not show cultivation, bore an odd pale purple hue. Beyond the village lay a long, narrow, twisting body of pale blue water. Pryor spotted a level spot that looked suitable for landing, clear of the tilled fields. His mocha colored fingers played the panel-buttons like the fingers of an organist ringing in stops, as he prepared Lab Able for its descent. Emerging from his ship, Pryor discovered that the pale purple fields were actually covered with a sort of low, tough shrubbery. It covered the sparsely-treed hills beyond the lake and seemed to fade into the deep misty blue of the afternoon sky. Although he had never seen a landscape like it, in all his roving over scores of planets, Pryor found it...