The plot of The Information is essentially simple; Richard, unsuccessful novelist and book reviewer, attempts to wreak revenge on his friend Gwyn, unaccountably successful novelist. Richard enlists the aid of Scozzy, a self-styled wild boy and drug dealer, to deliver physical punishments escalating in seriousness; after a tour of America in which Richard’s unsellable unreadable novel literally threatens the life of Gwyn and himself by causing a near-crash in a light plane, their relationship changes, and Gwyn loses the inhibitions resulting from his previous envy of Richard. Scozzy’s assaults prove counter-productive: only Richard suffers.
Even in this bald summary, it is clear that the book is much more than the story of two men, although you wouldn’t know this from the reviews it received at the time. This may have been because those reviewing it in Little Magazines were being cautious, since the book is scathing about the quality of British reviewing and questions the entire edifice of modern literary journalism.
The rivalry between Richard and Gwyn had a real-life equivalent in the friendship and sporting contests between Julian Barnes and MA which had run from their student days into adult life. Although MA has argued often that it is the job of writers to invent their fictions, he has often used real life as a source, in The Rachel Papers (teenager attending crammer school to get into Oxford), Success (art gallery assistant), Dead Babies (weekend of disasters with various friends and couples), and Money (screenplay writing in America). Since in The Information almost all description adopts the viewpoint of Richard, it is easy to assume that he represents MA (there are short passages where the narrator shifts to cover Scozzy and Gwyn, and MA appears speaking for himself briefly). This lazy equivalence is perhaps justified by MA’s ascription to Richard of his own experiences, including being given a set of bound volumes of the little magazine when he left, and seeing someone reading his book on an Underground train.
The book proved prophetic in its treatment of the other characters: the Julian Barnes friendship ended in the gap between Amis finishing the draft text and its being published, as a result of MA’s decision to drop Pat Kavanagh, Julian’s wife, as his agent. Agents too, particularly lazy agents, have a hard time in the book, particularly Gal Aplanap. MA does not reveal how much he drew on this event in finalising his text, but the rivalry, and its revelation as being not friendly but unfriendly, is structural. So much so that it seems legitimate to wonder whether the strength of Barnes’ reaction was partly in response to what must have read like a barely-veiled critique of his person and work (although it is doubtful that anyone would call his novels unliterary, Flaubert’s Parrot was nominated for a Booker prize, after all).
So rivalry is a theme, but not the main one. Richard himself says so: “Gwyn didn’t do it. The world did it.” (p. 140). It takes him a long time to realise that his campaign against fate is therefore aimed at the wrong target.
The novel ends with a paragraph which has been criticised as being meaningless or pretentious; but it provides, through back-references to previous events, an abstracted argument, a summary of ‘what the novel is trying to say’ (although Richard gives such questions short shrift: ‘It’s not trying to say anything. It’s saying it. […] It’s saying itself. For a hundred and fifty thousand words. I couldn’t put it any other way’. (p. 340).
The Man in the Moon is getting younger every year.  Your watch knows exactly what time is doing to you: tsk, tsk, it says, every second of every day.  Every morning, we leave more in the bed, more of ourselves, as our bodies make their own preparations for reunion with the cosmos.  Beware the aged critic with his hair of winebar sawdust.  Beware the nun and the witchy buckles of her shoes.  Beware the man at the callbox, with the suitcase: this man is you.  The planesaw whines, whining for its planesaw mummy.  And then there is the information, which is nothing, and comes at night. 
1 The Man in the Moon appears on p. 476 The Man in the Moon dates back to the time when humanity thought itself the centre of the universe; as we get older, we move towards knowing that we are temporary and unimportant; and we know we get older because policeman, doctors, professors even, look young.
2. Tempus fugit. Who has ever needed a skull as a memento mori? Who could forget?
3 This sentence appears on p. 197. We live with decay and dissolution; time’s arrow only points one way.
4 The critic is mentioned on pp. 432 and 476; he has lost his place in the world, his purpose, sidetracked by excess, and no longer matters to anyone.
5 The nun appears on pp. 213, 221 and 413. Why should anyone beware a nun? Partly because they act as a warning: they leave noone behind; but mostly I think because they know something. They already know the information, and accepted it: they are stronger than you.
6 The man at the callbox has cropped up on pp. 46 and 447-8. He is the man without home or family, desperately phoning around to find someone so that he doesn’t have to face death alone.
7 The planesaw whines on p. 172, as one of the urban sounds (although there is no such thing as a planesaw), reflecting the absence of community, the lack of fellow-feeling characteristic of modern life.
8 This sentence appears on p. 452.
It is clear from this analysis that the paragraph is carefully written, and, since it runs through the book, it follows that the novel as a whole is, too. Its style is a little flashy, but that is compensated by sentences, whole pages, of such beauty and clarity that the reader pauses in astonishment. This does some violence to credible characterisation, unfortunately: it is hard to believe that someone who thinks and speaks as eloquently as Richard does should write novels whose highest praise was that ‘nobody was sure they weren’t shit’, and it is notable that dim bland Gwyn and mad Scozzer share a common interior language with Richard, and MA.
So what is the information? The more astute of the reviewers says that it is death, but they are wrong. If the novel were about death, it would treat it more seriously: Anstice and Richard’s doctor are despatched quickly, simply, as jokes. Demi’s father, whose gradual decline in a rotting mansion is described, parodying Catholic Lord Marchmain in Brideshead Revisited, is also killed in a sentence. It is not death as such; the information is the knowledge of one’s own mortality. The world is telling you to start saying goodbye, to prepare in the face of inevitable, increasing humiliation.
Without blunting the force of this message, MA does suggest what can help in this task: love, children, and humour; throughout the book, these are quietly advanced as moral markers, good in themselves, and signifiers of goodness. Gwyn’s novels are shown to be bad partly by being humourless; Gwyn’s refusal to have children defines him as bad; Gwyn’s turning away from love is his badness. Because of this, MA is able to end his novel with Richard in what by any objective standard is a worse place than where he started, but being credibly happier all the same.