Wedge's Gamble (Star Wars: X-Wing Series, Book 2)

It is the evil heart of a battered and reeling Empire: Coruscant, the giant city-world from whose massive towers the Imperial High Command directs the war. The Rebels will invade this mighty citadel in a daring move to bring the Empire to its knees. But first Wedge Antilles and his X-wing pilots must infiltrate
Coruscant to gain vital intelligence information. Capture means death, or worse--enslavement by the vicious leader known as "Iceheart," Ysanne Isard, now
Emperor in all but name. And one of Rogue Squadron's own is already her slave, a traitor hidden behind a mask of innocence, working to betray both colleagues and the Rebellion itself.