 In her introduction to "The Best of Edmond Hamilton", Leigh Brackett called the story "a fine example of Hamilton's skill in encapsulating an enormous theme into the neat and perfect compass of a short story".The narrator, Arthur Wright, and his friend Hugh Dutton visit their former classmate, Dr. John Pollard at his combination house/laboratory.Pollard, a classic mad scientist, has been conducting research into the question of what causes the mutations that drive evolution.