The Jungles of Xen'drik: Secrets of the Forgotten Age
The land of Eberron is steeped in lore, stemming back to ages long past, millions of years before the current age. Originally brought to fruition by the battle of the three great progenitor wyrms: Syberis, Eberron, and Khyber, the land is now home to a great many peoples and creatures, all of whom are bound together by what is known as The Prophecy. Only the great dragons of Argonessen truly understand this event and its significance, but there is rumor that the Dragonmarked houses of the lesser beings are tied closely to the fate of the world, and that it is they who will decide the fate of Eberron.
A more detailed history can be found at the Eberron Unlimited Wiki