Producer David Heyman, who has been with the Harry Potter franchise from the very beginning and recently spoke in an interviewon working on the fifth film, Harry Potter and the Order of the Phoenix, waiting patiently for the last book in the series, and where they are on production of Half-Blood Prince.
Heyman on starting the series, many years ago:
I didn't have a clue. I knew there'd be seven books, but I had no notion that we'd be making two films, let alone seven. One was even a dream because so many projects end up in development (and no further). So I had no idea, but as the process evolved it became clear that it was becoming a phenomenon. By the time we were making the first film the third book had come out and they were one, two and three on the New York Times bestseller list, so we knew we were part of something special. But en then, when we had the opening weekend of the first film and all the office receipts were tallied, it was a complete surprise. And, of course, it set a very high bar that we have to meet now.
Heyman on the last book in the series, Deathly Hallows:
I'm sure I'll be a little sad when it's all over, but I don't know what happens. I have my thoughts, but I'm sure everybody has a theory. I can't wait to read the end, to read the last chapter, because while it's book seven it's one saga.