Grimrock

A few hints for your wizard.
After my 2nd playthrough and afterwards reading up in guides about stuff i may have missed i realized getting your wizard all skilled out is very, very tight.

If you wanna be able to cast all ingame spells and/or wanna get that steam sage archievment, you have to be very strict about skillpoint allocations.
To cast all 20 spells you will need the following skill setup:

Concentration: 3
Fire Magic: 5
Air Magic: 4
Earth Magic: 3
Water Magic: 3
Total: 18

On my 2nd playthrough i used a regular 4-man party (no farmer) with 1 human wizard. I discovered most secrets, cleared all areas and after the final (secret) boss i was level 14 (with my humans nearing 15).
Since my wizard had the skilled trait and i didn't use skill-books on her i ended up with 16 Skillpoints. 2 short of the goal. :/
Taking the +10% trait and wearing the +25% xp amulet might have made a difference but even then i would only have reached it at the very end of the game.

Long story short,
if you wanna max out your wizard, use all skill-books you find on him/her.

The topic is a bit misleading. There are 20 total spells. I've get Sage achievement with 0 points in earth magic. It requires total of 15 points and can be reached at lvl 14 without additional skillpoints.

The Sage achievement only needs to cast 15 different spells. I've been able to get it recently with Fire 5, Air 4, Earth 1, Water 3, Concentration 3, but I was not specifically trying to get it so there may be a quicker way or cheaper spells.

I misscounted. It's 20 spells total, not 16. So yeah you can totally get away without earth magic for instance.

Note: Don't give tips when tired. XD