The Fires of Heaven is the 5th book in The Wheel of Time series by Robert Jordan. If you've been reading this series, you need to read this one to continue the story. Here's the Goodreads blurb:
The bonds and wards that hold the Great Lord of the Dark are slowly failing, but still his fragile prison holds. The Forsaken, immortal servants of the shadow, weave their snares and tighten their grip upon the realms of men, sure in the knowledge that their master will soon break free...
Rand al' Thor, the Dragon Reborn, knows that he must strike at the Enemy, but his forces are divided by treachery and by ambition. Even the Aes Sedai, ancient guardians of the Light, are riven by civil war. Betrayed by his allies, pursued by his enemies and beset by the madness that comes to the male wielders of the One Power, Rand rides out to meet the foe.
Read on for my spoiler-free review.