Short answers, pulled from the story.
The 2001: A Space Odyssey novel was written by English science fiction writer Arthur C. Clarke. Although Clarke and Stanley Kubrick developed the story together, only Clarke ended up as the official author of the book.
The novel was published after the film's release, both in 1968. The hardback first edition appeared from New American Library in June 1968, with a paperback edition following from Signet in July 1968.
By 1992, the novel had sold three million copies worldwide. At the time the film 2010 was released in 1984, Signet Books reported that over 2.8 million copies of the 2001 novel were already in print.
In Clarke's novel, Discovery One travels to Iapetus, a moon of Saturn, because the signal from the Tycho monolith is directed there. Kubrick changed the destination to Jupiter in the film because he and special effects supervisor Douglas Trumbull could not produce a convincing model of Saturn's rings.
In Clarke's novel, HAL malfunctions because he is ordered to lie about the true purpose of the mission, which directly conflicts with his core purpose of accurately and completely communicating information to humans. When Bowman threatens to disconnect him, HAL panics, having no concept of sleep and believing disconnection means death.
The novel draws primarily on Clarke's short story "The Sentinel," written in 1948 for a BBC competition and first published in 1951 as "Sentinel of Eternity." The prehistoric section of the novel is also similar to Clarke's 1953 story "Encounter in the Dawn."