Tithe, Valiant, and Ironside by Holly Black are darker in tone than some of the other books on this list. They have been contested at times because they deal with themes like family strife, homelessness, and drug addiction. The first and third novels go together, while Valiant follows different characters in the same universe, each including a prominent gay or lesbian supporting character.  All three novels are urban fantasy, or as Black says, "suburban fantasy." In each novel, the protagonists are quickly pulled into a fast-paced, dangerous, exciting faerie world that thrives just below and alongside our normal human world, and must learn to navigate its twists and turns, or find themselves fighting for their lives.