Originally a thing of the divine realm preserved by the divine spirits of the Heavenly Mountains, this book contains the secrets to control all the fire in the world at will.  The Flame Cow King deceived the divine spirits and supposedly stole this book and brought it into this world.  After bringing the book out into this world, it is said, the Flame Cow King created his base, the Flame Mountain, with his new powers.  The power of the Book of Flames is behind the ever-raging fire of the Flame Mountain.