Twelve tales of the unknown from a master of science fiction Clifford D. Simak had a sublime ability to evoke a lost way of life. He spent his youth in rural Wisconsin, a landscape filled with mysterious hollows, cliffs, dark forests, and the Wisconsin River flowing in its deep-cut valley. As Simak wandered the countryside and the ridges, he peopled them with imaginary characters who later came to life in his stories. One such individual is Johnny, the orphaned farm boy of “The Contraption,” who stumbles upon a wrecked starship and receives a priceless gift from its owners. Another is the old prospector Eli, whose surprising discoveries on Mercury get him killed in “Spaceship in a Flask.” In “Huddling Place,” a man with paralyzing agoraphobia is the only one who can save the life of a dear friend on Mars—if he can bear to make the trip. And in the title story, aliens slowly take over Earth while humans leave it behind and head for the Homestead Planets. Each story includes an introduction by David W. Wixon, literary executor of the Clifford D. Simak estate and editor of this ebook.