While pricing still isn't known for these Books of XP, we do see the following pop-up, that looks like it might appear right underneath your XP meter at the top of the screen. It's likely this large 999 number will be the calculation of how many points you personally need to level up in your own game, giving you the chance to purchase a Book of XP right from the menu, if you so choose.
The picture at right is also the right size for one to be featured on the Specials page of the FarmVille marketplace, so we'll likely be able to purchase Books of XP in bulk there as well. If you're wondering why someone would purchase XP and levels rather than simply play the game, well... the only logical explanation I can come up with are those lower-level players that might want to skip the leveling up process to unlock new crops and items that might otherwise be unavailable to them currently. If there's another reason this is necessary, it's lost on me.
Either way, we'll make sure to let you know when these Books of XP launch in the game / marketplace, and how much you can expect to pay for such a convenience. Keep checking back with us for more.
Will you purchase a Book of XP, or are you fine playing the game and leveling up naturally? How much would you pay for such a book? Let us know in the comments.