When the report of the Apollo 13 mission was later published, NASA Administrator Tom Paine sent me a copy, and noted under Swigert's words: 'Just as you always said it would be, Arthur.' I still get a very strange feeling when I contemplate this whole series of events – almost, indeed, as if I share a certain responsibility.

Another resonance is less serious, but equally striking. One of the most technically brilliant sequences in the movie was that in which Frank Poole was shown running round and round the circular trick of the giant centrifuge, held in place by the 'artificial gravity' produced by its spin.

Almost a decade later, the crew of the superbly successful Skylab realized that its designers had provided them with a similar geometry; a ring of storage cabinets formed a smooth, circular hand around the space station's interior. Skylab, however, was not spinning, but this did not.deter its ingenious occupants. They discovered that they could run around the track, just like mice in a squirrel cage, to produce a result visually indistinguishable from that shown in 2001. And they televised the whole exercise back to Earth (need I name the accompanying music?) with the comment:

'Stanley Kubrick should see this.' As in due course he did, because I sent him the telecine recording. (I never got it back; Stanley uses a tame Black Hole as a filing system.)

Yet another link between film and reality is the painting by Apollo-Soyuz Commander, Cosmonaut Alexei Leonov, 'Near the Moon'. I first saw it in 1968, when 2001 was presented at the United Nations Conference on the Peaceful Uses of Outer Space. Immediately after the screening, Alexei pointed out to me that his concept (on page 32 of the Leonov-Sokolov book The Stars Are Awaiting Us, Moscow, 1967) shows exactly the same line-up as the movie's opening: the Earth rising beyond the Moon, and the Sun rising beyond them both. His autographed sketch of the painting now hangs on my office wall; for further details see Chapter 12.