Some readers may feel that the coincidence —or "correspondences" — that play a key part in this story are too unlikely to be plausible. But they were, in fact, suggested by far more preposterous events in my own life; and anyone who doubts that this sort of thing can happen is referred to Arthur Koestler's The Roots of Coincidence. I read this fascinating book only after completing Imperial Earth, thought that fact itself now seems somewhat improbable to me.
Even more improbable is the fact that when, on July 24, 1975, I appeared as a witness before the
House of Representatives Subcommittee on Space Science (in the very building libeled and demolished in Chapter 33!), I was able to quote extensively from Duncan's address to Congress in Chapter 41. This the House of Representatives' hearings now contain extracts from the Congressional Record for July 4, 2276, which should cause confusion among future historians.
The curious acoustic behavior of the spiny sea urchin, Diadema setosum, was observed by me on
Unawatuna Reef, off the south coast of Sri Lanka. I have never seen this recorded elsewhere, so it may be my one original contribution to marine biology.
Finally, my speculations about conditions on Titan were triggered by a series of papers that Dr. Carl
Sagan was good enough to send me. Needless to say, I am also indebted to Carl for many other
stimulating ideas, which any properly designed universe would be very foolish to ignore. "For if not true, they ware well imagined..."
ARTHUR C. CLARKE
Cinnamon Gardens, Colombo
January 1974 – January 1975