Just restarted game and wanna get the zephyr bow badly. Does anyone know if you can just go to the ruin and start the quest? If not is there a aeterium wars book I can find without starting the dawnguard quests? Any finally is zephyr a leveled weapon?

You could go directly to the Hall of the Vigil there is a copy of the book there...not entirely sure about going to the cave directy

There is a guy on here saying he went straight to the cave to do it and it progressed like it was started, but never gave it. Then he tried reading the book and still won't give.

So I'd say read the book first, seems like going right to the first cave might bug it.

There are copies of the book all over the place. One that I remember is in the Blue Palace in the Court Mage's room where the unusual gem and the enchanter are. Look on the bookshelf to the right of the door as you enter the room.

I'm on my way to solitude right now so it works. Thanks man.

Woops, my bad, I meant the palace of the kings in Windhelm, not the Blue Palace in Solitude. (I guess I had the Blue Palace on my mind because I am busy becoming Thane.)

Edit: but if you are Solitude anyway, check out the palace and the Bard's college. There might be copies there.