Knowledge is a Discipline Group whose traits revolve around magical theory. Knowledge disciples are stated to be drawn, mind and body, to the discovery of magic, primarily dealing with the deepening and discovery of magical knowledge as a whole. The disciplines within this group correspond with different levels of magical comprehension, from understanding and manipulating magical theory, to manipulating the qualities of magic as they apply it.
As said by Dean Fogg in The Girl Who Told Time, Knowledge is the discipline in which students are innately attracted to the discovery of magic. They are considered a bit of every branch with the possible difference that their objective is not to actively practice like other Magicians but to discover, reshape, or deepen the knowledge of magic.
- Meta-Composition: The understanding of the theories behind spells and the ability to reshape them. This was Julia's area in the 39 times she was at Brakebills.
- Metamagic: A discipline regarding magic that acts on other magic, or in itself. Fiberpunk, a hedge witch in the Murs Magicians, calls himself a metamagician. The only time he spoke to Julia, he said that he was drawing two-dimensional representations of three-dimensional shadows cast by four-dimensional objects. It is unknown if this a part of his discipline or just a project he did by himself.  However, when the Murs Magicians were attacked by Reynard the Fox, Fiberpunk attempted to use his discipline to open the door the god had locked. 
They live in the attic above the Brakebills Library, although with much more luxury than one would think at first.
Quotes on Knowledge
- "Thanks to intellectual explorers like you, magic is constantly growing and changing. Invest in vitamin D and a tanning bed - you won't get out much."