By knowing something's name, true name, a magical link can be created by associating oneself to it in a magical sense, in a similar way that one would if one had hair, nail clipping, or blood. One has to know exactly how to say the name, just knowing it is not good enough.
In the Dresden Files, all beings have a name and a Name. Anytime anyone says your name it touches you, but when a Wizard, or a supernatural being, says your Name, and means it, the effect is amplified a thousandfold.
Names with a capital N, have power. If a wizard has an entity or persons name, they automatically have a conduit, a way to home in on it.
Wizards collect names of creatures, spiirits and people. Like a huge supernatural Rolodex.  Some of the more powerful creatures in the Dresden-verse, like Ferrovax only need one part of a Name to influence said being. Some of the beings are too powerful, be very dangerous and probably not a good idea to call upon. However, there are countless lesser beings with lesser price tags and it's not so hard to get them to one's bidding.
A mortal's Name can change over time due to how their perception of themselves can change, whereas most supernatural beings' Name is static and unchanging.
In the seriesEdit
In Cold Days, Harry Dresden asks the small faerie, Captain Hook identify himself, but not to give his Name, just something to call him. Hook says "I'm called Lacuna by some." Upon request, removed the helmet which shrouded his face revealing herself to be a beautiful female faerie with long hair.
- Harry Dresden - Harry Blackstone Copperfield Dresden
- Elaine Mallory - Elaine Lilian Mallory
- Erlking - When a certain poem from Die Lied der Erlking is spoken under certain conditions, it forms the Erlking's true name and can be used to summon and trap him.
- Molly Carpenter - Margaret Katherine Amanda Carpenter
- Toot-Toot's - (true name secret)
- "Chauncy" - Chaunzaggoroth
- Lea - The Leanansidhe
- Mab - The Winter Queen