The Edge of the Knife, by H Beam Piper is one of the pivotal not felt was by Piper in his "Terra-Human Future History". Piper wrote this novella in 1957 at the height of the Cold War between the Soviet Union, and the United States of America, and seeing into the future could get you locked up in the sanitarium for dissolution all thinking. The protagonist, Charmers, a modern history professor has just such a problem.