The Witcher 2: Assassins of Kings

The Sense of Magic is the second to last ability on the magic skill tree. You will need to reserve 7 talent points to reach this ability. Keep leveling up until you have enough points, from there unlock 1 of each skill until you reach the Sense of Magic. Once you have this ability unlocked, return to your game and the achievement will unlock shortly after.

If you do not wish to waste points on this skill set, save your game before hand and reload your save once the achievement is unlocked.

Note: You cannot earn this while playing the arena mode. All ability unlocks tied to the arena are separate of the main game.

I found that there is a way to redistribute all your talent points in Chapter 3, if you spent them along the way. This makes it possible to benefit from them along the way however you see fit, but still unlock Master Alchemist, Master of Magic, and Swordmaster at that point.

However, it's part of the "From a Bygone Era" quest. I don't know if you can get this quest on Iorveth's path, but definitely on Roche's path.

In Chapter 2, you will have a quest involving examing grave stones near Malget's hut. Directly behind the hut is a trap door on the ground. If you make it down there and solve a puzzle dealing with candles, you'll get Malget's notes. They're encrypted, and you're instructed to find somebody who can read them.

Dethmold wants to buy them, but don't sell. If you still have the note when you reach Chapter 3, you can find a will-of-the-wisp door guardian in Loc Muinne, down in the sewers. Take the notes to a mage-smith (Bras of Ban Ard) in the central market area, and he'll explain the trick for using the notes to answer the guardian's password. Return to the guardian, solve the password puzzle based on Bras's info and Malget's notes, and enter the portal. Solve a puzzle with braziers, go through the unlocked door, and meet the "person" who can help you.

Save before talking, so it's easy to re-load afterwards. This allows you to un-assign all talent points, thereby letting you re-assign them as needed to get Master of Alchemy, Master of Magic, and Swordmaster. When talking to him, don't admit that you're not the chosen one and don't ask to get out of there. Ask him what the artifact does, then ask him to get started.

Each of these are on their respective talent trees to the left, right, and bottom. They're the second talents from the end in each tree.

This ability is one of the last on the Magic path, simply unlock it and the achievement is yours. (Note, will take you a couple of levels, unless you save all your points until you can unlock the magic path and go straight to this ability)

You cannot unlock this during the arena. (Thanks to Nyllon)