Board Thread:Show-Related Questions and Answers/@comment-91.140.37.79-20130329072829/@comment-4128816-20130329080131

I think the book was created by the Curse (so technically by Rumpelstiltskin since he created the Curse) as a way to ensure Emma would end up in Storybrooke once the time was right.

The Curse is activated, 28 years pass, Mary Margaret gives Henry the book, Henry reads the book and this confirms his prior theories on the town's strange conditions, Henry searches for Emma, finds her and Emma ends up in Storybrooke and Rumpelstiltskin's prophecy comes true.

Basically it's a kind of plot-device Rumpelstiltskin may have included to ensure things go according to plan.