Where to find the book you read. I know it is in the Dawnguard castle and the Volikhar castle, but I can't find it. I swear I've looked everywhere. Does anyone know where it is?

I believe second floor of Fort Dawnguard but not sure.

I dont know if its the same thing, but i found a book which started a quest a while ago, i havnt finished yet, but i think i found it a bookcase to the left when you enter the barracks type room, where everyone sleeps, with the hearth and firewood everywhere.. The room opposite the entrance basically..

In the barracks in Dawnguard, enter and it is on one of the bookshelves on the left side of the room.

Thanks all. This thread can be closed now.