For the benefit of those who have read my first novel, Against the Fall of Night, and will recognize some of the material in the present work, a few words of explanation are in order.

Against the Fall of Night was begun in 1937 and, after four or five drafts, was completed in 1946, though for various reasons beyond the author’s control book publication was delayed until some years later. Although this work was well received, it had most of the defects of a first novel, and my initial dissatisfaction with it increased steadily over the years. Moreover, the progress of science during the two decades since the story was first conceived made many of the original ideas naive, and opened up vistas and possibilities quite unimagined when the book was originally planned. In particular, certain developments in information theory suggested revolutions in the human way of life even more profound than those which atomic energy is already introducing, and I wished to incorporate these into the book I had attempted, but so far failed, to write.

A sea voyage from England to Australia gave an opportunity of getting to grips with the uncompleted job, which was finished just before I set out to the Great Barrier Reef. The knowledge that I was to spend some months diving among sharks of doubtful docility was an additional spur to action. It may or may not be true, as Doctor Johnson stated, that nothing settles a man’s mind so much as the knowledge that he will be hanged in the morning, but for my part I can testify that the thought of not returning from the Reef was the main reason why the book was completed at that particular time, and the ghost that had haunted me for almost twenty years was finally exorcised.

About a quarter of the present work appeared in Against the Fall of Night; it is my belief, however, that even those who read the earlier book will find that this is virtually a new novel. If not, at least I hope they will grant an author the right to have second thoughts. I promise them that this is my last word on the immortal city of Diaspar, in the long twilight of Earth.