It is extremely difficult, if not impossible, to translate a book into a movie. The problem has to do with one's imagination: words in a book conjure up images that are highly personal and subjective, and any attempt by a third party to lend form to them ends up disappointing. Harry Potter and the Sorcerer's Stone is no exception in this regard, but fortunately, the imagery presented is awesome and wondrous in its own right.
The film is made strictly by the book: Harry Potter (Daniel Radcliffe), a young boy mistreated by his foster family, learns that he is special and comes of age... in the Hogwart's School of Magic (!) where he learns wizardry, plays Quidditch and fights an evil despotic wizard (who does not turn out to be his father).
While the movie stays fastidiously true to Joanne Rowling's book, perhaps one of the best adaptations ever, the adage that a picture is worth a thousand words doesn't hold true here. For the most part, from the initial victory of the baby Harry Potter upto the Quidditch match, a lot of the details are skipped. What we're presented with is a jump from one scene to another (sometimes too quickly) that illustrates with painstaking effort the magical realm that Rowling has constructed in her series. For example, while the opening sequence shows Professor Albus Dumbledore (Richard Harris) turning out the lights in a street, Professor McGonagall (Maggie Smith) changing to her true form from being a cat, and Hagrid (Robbie Coltrane) bringing Harry on his flying motorcycle, we're not really shown the celebration of Lord Voldemort's fall. This isn't criticism but just an observation; in fact, I think doing this is especially okay if one is familiar with the Harry Potter books, but it does impart a sense of urgency in the beginning portions of the film.
