SOURCES AND ACKOWLEDGMENTS
The writer of historical fiction has a peculiar responsibility to his readers, especially when he is dealing with unfamiliar times and places. He should not distort facts or events, when they are known; and when he invents them, as he is often compelled to do, it is his duty to indicate the dividing line between imagination and reality.
The writer of science fiction has the same responsibility, squared. I hope that these notes will not only discharge that obligation but also add to the reader's enjoyment.