Legilimency

Legilimency is, in the Harry Potter continuum, the art of magically penetrating someone's mind. It is not exactly synonymous with "mind reading", as practicioners can, at least in some cases, manipulate the victim's mind as well. A practicioner is known as a Legilimens.

The art of shielding one's mind from such invasions is known as Occlumency.

(More about Legilimency at the Harry Potter Wiki.)