Marvel Knights was an imprint of Marvel Comics. Dealing with more mature themes than the regular imprint, it was intended more for teenagers rather than children. However, it did not deal with the adult themes touched on by the MAX imprint.
The imprint originated in 1998 when Marvel outsourced four titles (Black Panther Vol 3, Daredevil Vol 2, Punisher Vol 4, and Inhumans Vol 2) to Joe Quesada's Event Comics company; Event hired the creative teams for the Knights line while Marvel published them. The imprint has since been folded back into Marvel's standard methods of publication, and is used to single out Marvel's "edgier" titles. The Marvel Knights imprint is essentially the successor to Marvel Edge.