Ok, all the potions in the game tend to affect things in a 'clear' manner to me except for potions that boost Intelligence. If you already know a spell, and have it memorized, what does boosting your IN do for it? Does it make the spell more powerful? The only thing I have used these potions for is when fighting Mind Flayers... as soon as I see that Intel drain symbol pop up, chug-a-lug and I am safe for a bit longer. If there is a more noticable and/or beneficial effect, I would sure like to know what it is so I can take advantage of them.

It keeps ur high lvl spells from being unmemorized by int draining creatures, gives a bonus to lore and not sure how long it lasts but if it lasts 12 hours u can get some more spells.

In my custom orc-only party they are quite handy when I need to identify large amounts of low-level items.

What???

Genius - 15 turns
Mind Focusing - 12 hours

I am sure you have your manual, so open page 118 where it is stated.
Higher INT brings following bonuses:
-More spell levels available (eg. you cannot learn 9th level spells with INT of 17 or less)
-Higher "to learn spell" percentage (100% at INT of 24)
-More spells to learn per spell level (all at INT of 19)
-Lore bonus

I meant more spells per lvl, and i dont have my manual(curtesey of an annoying little sister)

Well, I have read the manual, but I guess I just don't understand what it means (I have not played D&D in any other form than the BG games). So...

When it says:
-More spell levels available (eg. you cannot learn 9th level spells with INT of 17 or less.
Is this referring to being able to have more spells in your spellbook? For example, I could have 9 spells of Level 5, and now I drink the potion, and I can now have 12 spells in my book for level 5? And do they disappear after the potion wears off?

-Higher "to learn spell" percentage (100% at INT of 24)
Not sure what this is at all... unless it refers being able to copy a scroll to your spellbook. If so, I find this nearly useless anyway because I have never failed at this.

-More spells to learn per spell level (all at INT of 19)
Does this mean if my mage has only 2 level 8 slots for casting, drinking this potion would allow me to cast more lvl 8 and maybe some lvl 9 spells (for the 12 hours)? So, if I drank the potion, picked the spells I wanted to be able to cast after my resting, and then rest, I would be able to cast those spells? And do these 'learned spells for the day' disappear after the potion wears off?

Finally, I did look in my BG2:SoA manual, and didn't find what you were referring to on pg 118 (or 11, or 18). This is the manual that came with my game, so if you are referring to something else, please let me know what it is. Thanks!

Well, doesn't matter, yes? We explained it already.

Mr Flibble-

To your "when it says" post:

-Not really. It's saying that without 18 intelligence, you can't memorize level 9 spells. If you have Throne of Bhaal, they've removed that rule (otherwise Nalia, Imoen, and Jan wouldn't be able to memorize 9th level spells and everyone would grab Edwin).

-That's exactly what it means. And trust me, if you try to scribe 10 or 20 scrolls in a row, you will fail some. You're just getting lucky- the game "rolls" dice to see whether or not you pass...and other actions you do must be getting the low dice rolls. It stinks to have a 9th level scroll go down the drain just because you failed a check.
Also, IIRC, at any level below Core (it might be a checkable option, I don't really remember), you'll automatically learn anything you try to memorize.

-That actually means what you thought the first one did. It means that below 19 intelligence, there's a limit to how many spells you can know per level (I don't remember the whole table- it's in the BG2 manual...but iirc it's 9 per level at 18 int and less at lower ones). If you have 19 or above, you can memorize as many as you want (which is important not only spellwise but experiencewise- each spell you scribe to your book gives you experience. Memorizing 9 level 9 spells would give you an 81,000 point experience boost for your party).

Where was it explained? He gave some answers that I didn't understand, I restated my questions in response to his answers, and you just say 'We explained it already.'? And anyway, yes it does matter, I would like to find the section on it and read up on because it doesn't make sense to me right now.

Ok, so tell me if I haven't gotten this correct (and thanks to all of you helping me through this!!!!!!!)

1) Even though it's a temporary boost in Intelligence (from the potion), if you memorize a spell you didn't have access to before the potion, that spell is going to last in your spellbook after the potion wears off?

2) You can only place the spells in your spellbook and gain the experience points from it, but you cannot rest and be able to cast those new spells you learned with the potion's Intelligence boost?