Helblindi:
Hi,
I like to think I know the rules for WHFB fairly well, however, I’ve never bothered to look into the magic phase, as I’ve been playing dwarves during my first year. So, now that I might be using magic soon as a CD, I have one very stupid question:
If player A casts a certain spell for the first time that game, can player B read what the spell does before dispelling?
I’m guessing yes, especially when it’s from one of the lores from the BRB, but can player B also read it if it’s, say, from lore of Hashut, and so only in player A’s AB?
I know this is also relevant for dispelling stuff as a dwarf, I’m not sure how it’s possible I still don’t know this :o
Thommy H:
Yes. Spells are rolled in the presence of the other player at the start of the game, so the assumption is that everyone knows what they each do. You don’t get a bonus for owning your opponent’s book and reading up beforehand.
Helblindi:
Thanks a lot! I thought so, but I needed confirmation, and BRB doesn’t seem to explicitly say it.
Malorndk:
To put everything out of question:
"The only thing you are allowed to keep secret is your magic items!"
So when you are presenting your armies before battle, youll have to tell your opponent everything he wants to know about:
Equipment
Statlines
Special Rules
Magic
Vampiric Powers/Demonic gifts/Big Names and so forth.
If you are allowed to keep something hidden (Like fx a Dark Elf Assassin) it will be clearly stated 
Helblindi:
Aha, thanks. I had a hunch it would be like this, but it’s nice to see it plainly written like that.