I believe it has always looked like a book (").

From a technical point it is a scroll, but Krys made the image look like a book (it has it's own image, if you look closely you can see the IBM letters). Maybe he can modify the image?

I always thought it looked like a ?, like other scrolls.

Oh nice, I didn't even look close enough at it to notice the letters. Nice detail! Up to you whether it should be changed, I suppose. Just seems odd that it looks like a book when it's a scroll (though now that I think of it, what's stopping the guild manual from being a book, in-game?)

It is a nice touch, but to preserve the nasty surprise I think it should either look like a scroll, or else be redefined as a book and made to look like a spellbook.

As a spellbook it will effectively discourage melee classes from even attempting to read it.
As a scroll it still has a potential to screw you up no matter what class you're playing.
Its sole purpose has always been to make your life miserable hasn't it?
Making it a spellbook narrows the potential "audience" for this practical joke.

There are already quite a few scrolls that will screw you up when reading it (scrolls of amnesia, danger, ill fate, destruction, monster aggravation... not to mention 95% of cursed scrolls). Also, the IBM guild manual is always labelled "irk gleknow mizk", so to someone who knows that, there will be no further surprises from it whatsoever.

Apart from the tomes of order/balance/chaos (which all have weights that aren't 100s, for easy identification), reading a book has no ill effect, except when your literacy isn't great. Once at 100 Literacy, there are basically zero surprises from reading any 100s spellbook (even cursed ones aren't bad to read, unlike scrolls). Reading UnID'd books is completely safe, whereas you almost certainly want to ID any scroll before reading it (including finding its B/U/C status).

As the IBM guild manual is already ridiculously rare, I see no real issue with just turning it into a book. THAT'S going to be the only way it will ever screw up a player more than once.

(Maybe it might also be a good idea to remove the "IBM" from the item graphic? I'm on the fence with that idea, the letters aren't terribly obvious unless you are actually paying attention to that detail...)

If it looks like a book in NotEye, it should probably look like a book in ASCII then as well.

Changed IBM Guild Manual icon to represent a scroll rather than a book.
Now ASCII and Graphical are consistent on this matter, issue can be closed :)

Done.