Item from The Black Company by Glen Cook
The most dangerous knowledge in the world — know a sorcerer's true name and you own them. The entire power structure of the north runs on this one secret.
In Cook's world, true names grant power over sorcerers — knowing a wizard's real name allows you to compel, bind, or control them. This is how the Dominator created the Taken, how the Lady maintains control over them, and why every sorcerer in the world operates under a pseudonym. The mechanics of true-name magic underpin the entire political structure of the north. The Lady rules because she knows the Taken's names and they don't know hers. The Taken serve because they must, not because they choose to. The Dominator is kept imprisoned partly by the wards on the Barrowland and partly by the Lady's knowledge of how to reinforce them — which requires knowing his name. True names are the series' metaphor for information as power — in Cook's world, the most dangerous weapon isn't a sword or a spell, it's a secret.
True names have no physical form — they're knowledge, the most dangerous kind. A word, a name, spoken at the right time by the right person, and the most powerful sorcerer alive becomes a puppet. The Lady guards her true name (Dorotea Senjak) with lethal thoroughness. The Taken guard theirs. The Dominator's name is the key to his prison.
Also known as: True Names, True Name Magic, Name Magic