The Folk of the Air Series 4 Books Collection Set By Holly Black:

The Cruel Prince:
One terrible morning, Jude and her sisters see their parents murdered in front of them. The terrifying assassin abducts all three girls to the world of Faerie, where Jude is installed in the royal court but mocked and tormented by the Faerie royalty for being mortal. As Jude grows older, she realises that she will need to take part in the dangerous deceptions of the fey to ever truly belong.

The Queen of Nothing:
After being pronounced Queen of Faerie and then abruptly exiled by the Wicked King Cardan, Jude finds herself unmoored, the queen of nothing. She spends her time with Vivi and Oak, watching reality television, and doing odd jobs, including squaring up to a cannibalistic faerie.

The Wicked King:
Jude has tricked Cardan onto the throne, binding him to her for a year and a day. But the new High King does everything in his power to humiliate and undermine her, even as his fascination with her remains undimmed. Meanwhile, a traitor in the court is scheming against her. Jude must fight for her life and the lives of those she loves, all while battling her own complicated feelings for Cardan. Now a year and a day seems like no time at all . . .

How the King of Elfhame [Hardcover]:
Before Cardan was a cruel prince or a wicked king, he was a faerie child with a heart of stone. In this sumptuously illustrated tale, Holly Black reveals a deeper look into the dramatic life of Elfhame's enigmatic high king. This tale includes delicious details of life before The Cruel Prince, an adventure beyond The Queen of Nothing, and familiar but pivotal moments from The Folk of the Air trilogy, told wholly from Cardan's perspective.