In 1968, 2001: A Space Odyssey was released into cinemas worldwide, and has remained one of the most influential and talked about science fiction films ever. Some find it a poetic masterpiece; to others it is a tedious overlong film with no point. Yet it remains influential and unique, even today.

2001 was written by Arthur C Clarke, and was directed by Stanley Kubrick.

The plot to the film is seen as being either easy to understand, or totally incomprehensible. Some consider the plot to be unimportant as the film is breathtakingly beautiful, especially the space sequence accompanied by Johann Strauss' Blue Danube Waltz, and the equally moving Moon-Earth-Sun alignment played out to Richard Strauss' Also Sprach Zarathustra.

The film has four different parts: The Dawn of Man; The Moon; Mission to Jupiter; and Beyond the Infinite. At the end of each sequence, man is confronted by a Monolith, a sentinel left by a vastly superior alien race. To reveal more would certainly spoil enjoyment of the novel, although the film itself is a visual experience; knowing what is happening can be seen as irrelevant.

Stanley Kubrick's response to people asking what the film is about had this to say:

I don't like to talk about 2001 much because it's essentially a non-verbal experience. Less than half the film has dialogue.

How could we possibly appreciate the Mona Lisa if Leonardo had written at the bottom of the canvas: 'The Lady is smiling because she is hiding a secret from her lover.' This would shackle the viewer to reality, and I don't want this to happen to 2001.

Arthur C Clarke's response to what the film is about is his novel, 2001: A Space Odyssey, although he has also said:

If you understood 2001 completely, we failed. We wanted to raise far more questions than we answered.

Although, if you wish to understand the film, having read the novel beforehand certainly helps explain what is happening.

In 1964, Stanley Kubrick - a successful director of films such as Dr Strangelove, Spartacus (and who went on to direct A Clockwork Orange, The Shining, Full Metal Jacket and Eyes Wide Shut) first contacted Arthur C Clarke about making the 'proverbial good science fiction movie'. Kubrick felt that all the science fiction films that had existed before were often too horror-based, with the emphasis on alien monsters, and Kubrick wanted to create a work of art capable of arousing wonder and awe.

MGM agreed to finance the film in February 1965. Stanley Kubrick did not come up with the title '2001: A Space Odyssey' until April 1965, 11 months after he and Arthur C Clarke started the project. Before that, it had been known as 'Journey Beyond The Stars', a title that neither were keen on, yet was better than 'Universe', 'Tunnel To The Stars', 'How The Solar System Was Won' and 'Planetfall', the other suggested titles.

Originally, the film was going to open with interviews with experienced scientists, but it was felt that this would interfere with the film. Another factor was that Arthur C Clarke felt that there was no need to educate the audience as the contemporary astronomical events of the time were doing it instead.

After the film was 'finished,' it originally ran two hours and 41 minutes long, yet 19 minutes were trimmed off before release. Kubrick later said:

The people who like 2001 like it no matter what its length, and the same holds true for the people who hate it.

One thing which has caused a lot of debate is the question, which came first, 2001 the film, or 2001 the novel? Normally when a film and a book of the same title exist, either the film is a dramatisation of the novel (as was the case in the film Dune) or sometimes a novelisation is made of the film, for example Isaac Asimov's Fantastic Voyage. Neither was true for the 2001 novel/film symbiote.

When Stanley Kubrick contacted Arthur C Clarke about the film, they used Arthur C Clarke's short story The Sentinel, written in 1948, as the base1. The Sentinel is a short story about an astronaut who discovers an alien artefact on the moon which, when discovered, sends a signal informing the aliens that mankind had advanced enough to be able to cross to the moon.

This is essentially the same as the second part of the film, where Heywood Floyd travels to the moon to the monolith, which relays a signal of discovery to Jupiter. Other Arthur C Clarke novels influenced the film, for example the EVA pods seen onboard Discovery have been described in many of Arthur C Clarke's stories.

Yet in 1964, before the film was made, Stanley Kubrick originally decided that he and Arthur C Clarke would work on the novel together first, as a basis of what the film would be. However, as Arthur C Clarke wrote:

The result was far more complex... both novel and screenplay were being written simultaneously, with feedback in both directions... I felt that when the novel finally appeared it should be 'by Arthur C Clarke and Stanley Kubrick; based on the screenplay by Stanley Kubrick and Arthur C Clarke' - whereas the movie should have the credits reversed. This still seems the nearest approximation to the complicated truth.

Arthur C Clarke wrote the novel throughout 1964 to 1968, and at several points he felt that he had finished. The first time was in December 1964, although later several chapters had to be re-written or removed from the novel in order for it to fit in with the latest ideas Arthur C Clarke and Stanley Kubrick had together2. This resulted in a bit of tension between the two, when in April 1966, Clarke felt that the novel was finished and wanted to publish it, yet Kubrick disagreed.

The main difference between the novel and the film is that in the film, the 'Star Gate' is found in the orbit of Jupiter, yet in the novel, it is on Japetus, a moon of Saturn. The film had originally intended to use Saturn, yet the film makers were unable to make Saturn look convincing. Arthur C Clarke has said:

One of the reasons why I was drawn to Saturn... and stuck with it in the novel... is that its ninth moon, Iapetus, is one of the most mysterious bodies in the solar system.

Con Pederson, 2001's special photographic effects supervisor, has said:

Jupiter was selected over Saturn, because to do Saturn meant getting a convincing Jupiter first... and then finding a way to put rings around it. Best way to do the planet was not the best way to do the rings; they could not be made at the same time.

In the novel, Arthur C Clarke referred to the moon as Japetus, and not, as it is more commonly known, Iapetus. This was apparently based on W Ley and C Bonestell's 1949 volume The Conquest Of Space. For Arthur C Clarke's sequels to 2001: A Space Odyssey - 2010: Odyssey Two, 2061: Odyssey Three and 3001: The Final Odyssey, he has used Jupiter, and its moon Europa, not Saturn and Iapetus.

• All the displays for the computer screens in 2001 showing the ships docking and so on, were, like the Hitchhiker's Guide To The Galaxy television series, not computer graphics at all. They were, in fact, animations, drawn by artists rather than generated by computers.

• Scenes shot for 2001 but not used in that film were included in The Beatles' film Magical Mystery Tour. This was the cloud sequence seen with the instrumental song 'Flying' before meeting the Magicians.

• NASA was, at the time work on the film started, spending the same amount of money as 2001's total budget every day - $10,500,000.

• In 1969, Planet of the Apes won an Oscar for Best Make-Up for their apes, despite looking a lot less realistic than the apes in 2001. Arthur C Clarke said, '2001 did not win the Academy Award for make-up because judges may not have realised the apes were actors.' 2001: A Space Odyssey won an Oscar in 1968 for Special Effects, as well as BAFTAs for Cinematography and Production Design.

• The skull-smashing sequence was the only one not filmed in a studio.

• HAL's initials are, coincidentally, one letter behind those of IBM, a major computing company. Arthur C Clarke states that this was a coincidence and that the name came from the fact that he was a Heuristically programmed ALgorithmic computer.

• In the scene in which a leopard is seen next to a zebra it had killed, the 'zebra' was a horse painted black and white.

• Dr Floyd's daughter was played by Kubrick's daughter Vivian.

• One technical error that was missed can be seen when Dr Floyd sucks his food in zero gravity. Instead of staying in the straw, the food slips back into the container.

• In 1984, a second film 2010: The Year We Made Contact was made by Peter Hyams, based on Arthur C Clarke's novel 2010: Odyssey Two.