Harry Potter (HP) is a teenager, studying at the Hogwarts school of Witchcraft and Wizardry. Harry was born from the mind of british writer Joanne Kathleen Rowling (JKR), when she was a teacher at Portugal, back in 1993.
By late October 2001, HP was roughly 14, or - better measure his age this way - 4 books and nearly 1 movie old.

Harry Potter is special for many fictional reasons, and for many "real life" facts. The thing is that the first HP book was only published in 1997 and that a mere 3 years period was enough to catapult JKR from a rather anonymous and difficult existence (divorced mother, living on Scottish public assistance) to total fame and fortune.

The Potter phenomenon is indeed a TRUE phenomenon, never before seen. There are more children (and adults) knowing about Harry's troubled past (both parents dead, when trying to save him from the #1 dark wizard - Lord Voldemort) and virtuous present (he literally saves lifes, book after after book), than knowing about any other person, fictional or real.
In other words, in a world where children are often referred as electronic entertainment junkies (tv, videogames, digital music, etc...), the Potter character somehow managed to rise from the literature underground, and grow a horde of supporters, of all ages, though having roots and expanding from the younger stratus.

So here you have it - another phenomenon fact: how is it possible for such a snowball to form, in such a record time, only pushed by children?! Quite a Hogwarts' mystery... A rather (sad) comic answer comes from some people who point Potter as a work of the Devil!! Yeah, I am just as shocked as you are.
Peek at http://www.pawcreek.org/Harry%20Potter.htm and read the opinion of this lunatic-sick-abnormal dude, that signs as Joseph Chambers. He writes an article entitled "Harry Potter and the Antichrist", where such beyond commentary sentences like "Without question I believe the Harry Potter series is a creation of hell helping prepare the younger generation to welcome the Biblical prophecies of demons and devils led by Lucifer himself", are a common place... Doesn't this revolt you?! E-mail me your POV (Point-Of-View).

While sick people come up with sad ideas like the aforementioned one, others have a much healthier view, and notice nothing but the evidences: Potter is fun, Potter magnets people of ALL ages back to reading, and Potter even contributes to a more positive attitude towards schools.

I finished The Philosopher's Stone (book #1), The Chamber of Secrets (book #2), The Prisoner of Azkaban (book #3), and I am halfway through The Goblet of Fire (book #4), in a month...

As you read the whole saga, it gets obvious that JKR's writing style improves, book after book, and - sometimes - chapter after chapter. It is crystal clear when Rowling is restarting the story, and when she has been enduring for hours. You can just feel it: you sense a rhythm and a coherency that sometimes breaks...
JKR's writing style grows, as Harry grows. The 1st chapter of the forth book, could fit any decent "adult" horror fiction. To be honest, I think that Joanne didn't have to try hard to write "for children" (the books' main market audience): her easy words, clear constructions and healthy punctuation are just wide reaching enough, to (also) grab youngsters, but I don't believe the author pinpointed who to reach. "Adults" should *also* appreciate such a clean writing style, and if they somehow connote (the non-existing) deep, nested, confusing paragraphs with "content for mature audiences", they are distorted.

However, on relative terms, the Potter books just don't hit the fantasy pinnacle that - for example - any JRR Tolkien's paper can achieve. And some strategies can be annoying, such as the constant Potter vs Malfoy war, where Malfoy always loses and never learns... it just doesn't feel natural.
Professor Snape's blind and rude attitude towards Potter also doesn't glue on what's supposed to be a brilliant wizard, as he teaches at Hogwarts...
And Hermione Granger is somehow void of sexuality... or how can it be explained that hormonal bombs, as herself and 14 year old mates, like Harry and his best friend Ron, never blush, talk or think carnal matters? Strange. Magical? May be this justifies the "children audience" unofficial label.

Once you grab a Potter book, you just devour it. That's what happens with me. The Potter phenomenon is now a true franchise: you have everything Potter, from pencils to brooms... and the ready-before-Christmas Chris Columbus movie, casting the mega lucky Daniel Radcliffe, as young Harry. Strangely... doesn't Radcliffe have brown hair?! Wasn't Harry's hair supposed to be black?! Hum...