@K_A
 
I wonder if you’re right! I wonder if Luna will be the one to help Twilight and friends resolve the story in s03e03. Oh goodness. I can see every pony site EVER just exploding if episodes started to end with “Dear Princess Luna”.
 
I’ve been a fan of the show since 2010. I’d have never dared dream of such a thing. Even now, I’m trying not to get too excited. Oh man! :D

Luna’s gonna be teaching Twilight!

Hmm, Maybe the book is Equestria’s secret History, dealing with the past techno-wizardry of the era and the Interstellar wars that Celestia and Luna fought along side the mane six’s ancestors one hundred thousand years ago. Oh and the ponies in that era were anthro.

OMG LUNA AS TEACHER!!!!

Watch as it never gets mentioned again.

“God damn, that ass.”

@FanOfMostEverything  
Fanname accepted.

Until it has a canon name, I call that book the Black Tome of Future Plot Relevance

I think the Luna-as-teacher theory may be right. Those may Luna’s teaching materials.
 
My theory is part of the test involved Twilight using and controlling dark magic without corruption. There may be darker magic studied by Starswirl and mastered by Luna. Aside from “Dark is not Evil,” those new studies may be thematically about learning to control one’s emotions and channel “negative energy” productively. (Future episode spoiler) The alleged bullying episode for example would fit in well with that.
 
The book of course could be a plot device for something else, but this lends further credence to Luna teaching Twilight. Imagine Luna fans listening to an episode closing with “Dear Princess Luna.” That’ll be an episode that’ll break Ponychat and Derpibooru for sure.

It’s Luna’s fanfiction collection.

a clopfic

I.need.to.know.what.is.in.that.book…

Look on the cover! Stars and a swirl. Starswirl the Bearded!

There is last page of history book.

It’s a Lisa Frank trapper Keeper where Luna has all of her teenage poetry recorded.

What the hell is in that book?

@Background Pony  
WTF has that to do with this?

Luna has a Little Black Book. hmm…

Necronomicon!

Pff, and people got mad about a winged Twilight for nothing.

I bet that notebook would be an interesting read.

THAT FREAKING BOOK! IT INTRIGUES ME!