I was a research assistant for an academic book on Anthony Burgess, so I know the book and the movie well. What people who've only seen the Kubrick film or only read the edition of the book initially released in the US may not know is that the original English edition (now available in the US) follows Alex for some time after the famous line: "I was cured all right." If you by chance get to listen to the Audiobook version with the preface by Anthony Burgess, he explains the how and why of the discrepancy, so I'll not repeat it here. Another big difference between the book and the film is that the characters as originally drawn are all younger than portrayed in the film. I think Alex was 15 at the start of his narrative. (The other movie I remember thinking this of was Alex Cox's Sid & Nancy. All the actors cast were substantially older than there real-life counterparts) I definitely understand why the studio changed this detail; they had enough troubles getting the film screened as it was. Many critics at the time said the film glorified sexual violence, which was even more unforgivable because of the movie's high level of craft. If I'm dealing with adults, my inclination is to leave it to adults to make that judgement for themselves. I will note that I know thoughtful people who consider A Clockwork Orange to be high art, but have no use for rap music, because they see it as glorifying violence without redeeming social value.
If anyone from SOH does listen to the Audiobook preface, I'd be very interested in hearing what you thought of it. IMO, Burgess seems to respect Kubrick's work but feels that it undermines one of his novel's central questions in its ending. This is nothing unique with writers and filmmakers. Gore Vidal claims he never watches the movie versions of his books, because once the author signs away the film rights, he loses all control over what the studio does with the property. Stephen King has even more serious issues with the way Kubrick handled The Shining, which IMO was King's best work as an author. I think he was even one of the backers behind the Sci-Fi miniseries, but couldn't swear to that.
JAMES