If the second book in the Twilight series is Eclipse, why is the second movie New Moon?

Question by *Miss_Autumn*: If the second book in the Twilight series is Eclipse, why is the second movie New Moon?
A friend of mine recently finished reading the first book (I didn’t get that far personally) but at the back of the book there is an ad that says “continue reading the saga in Eclipse”. Meanwhile the next installment of movies that is currently in pre-production and they’re wrangling up actors for is New Moon that is supposed to pick up where Twilight left off, but they’re also saying that they intend to make movies of each book. How does that work?
I wonder why they would have an ad for the third book saying to read that next instead of the second, if that is the case.
There is nothing at all in her copy that mentions New Moon being the second in the series

Best answer:

Answer by thewordsicantsay
new moon is the second book. Eclipse is the third.

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