character explains to him, 'It's as easy to transfer a pattern from a dead brain as a living one'), so that a businessman named Mr. Dorchin could charge companies to use the townspeople as test subjects for new products and advertisements. Something close to the notion of mind uploading is very briefly mentioned in Isaac Asimov's 1956 short story The Last Question: "One by one Man fused with AC, each physical body losing its mental identity in a manner that was somehow not a loss but a gain." A more detailed exploration of the idea (and one in which individual identity is preserved, unlike in Asimov's story) can be found in Arthur C. Clarke's novel The City and the Stars, also from 1956 (this novel was a revised and expanded version of Clarke's earlier story Against the Fall of Night, but the earlier version did not contain the elements relating to mind uploading). The story is set in a city named Diaspar one billion years in the future, where the minds of inhabitants are stored as patterns of information in the city's Central Computer in between a series of 1000-year lives in cloned bodies. Various commentators identify this story as one of the first (if not the first) to deal with mind uploading, human–machine synthesis, and computerized immortality. Another of the "firsts" is the novel Detta är verkligheten (This is reality), 1968, by the renowned philosopher and logician Bertil Mårtensson, a novel in which he describes people living in an uploaded state as a means to control overpopulation. The uploaded people believe that they are "alive", but in reality they are playing elaborate and advanced fantasy games. In a twist at the end, the author changes everything into one of the best "multiverse" ideas of science fiction. In Robert Silverberg's To Live Again (1969), an entire worldwide economy is built up around the buying and selling of "souls" (personas that have been tape-recorded at six-month intervals), allowing well-heeled consumers the opportunity to spend tens of millions of dollars on a medical treatment that uploads the most recent recordings of archived personalities into the minds of the buyers. Federal law prevents people from buying a "personality recording" unless the possessor first had died; similarly, two or more buyers were not allowed to own a "share" of the persona. In this novel, the personality recording always went to the highest bidder. However,