Assignment in Nowhere — Keith Laumer

THE COMING OF THE BLIGHT It seemed as though the world was eroding right under everyone's feet. Stories disappeared from magazines; the baron's silver coat of arms, polished in the morning, was pitted with corrosion by afternoon; toadstools were springing up from every corner. And these were but the first signs of the coming plague, a cancerous orgy of patternless vitality seeking to engulf the world... TO STEM THE TIDE Carefree Johnny Curlon, indelicately plucked from his fishing boat one evening, is bluntly informed by high powers that he is a man destined for a role in great affairs: only his unique powers can prevent the coming probability crisis that threatens to turn the world into bubbling chaos...