anyone know if there will be books or something the digs deeper into the dawnguards back story? i know the quests and whatnot will give like an overview but i wanted to know if they'rd be books you can find and read

Possibly. Time will tell.

Only the beta testers know for sure.

I'm sure we'll get plenty that'll dig deeper.

would not be elder scrolls if such things did not exist
i am sure the storyline or books some sort of background will become available to see

There's definitely a backstory to the Dawnguard that you can hear from the characters in the castle.