From back cover:
The Heart of the Wild is a resource for The One Ring: Adventures Over the Edge of the Wild describing the lands of the River and the Forest – the Vales of Anduin along the banks of the Great River, and the trackless forest of Mirkwood to the east. It expands on the descriptions given in the Loremaster’s Guide, offering new sanctuaries and new perils for the players to discover. Each region is described in detail, listing potential friends and foes, sites of interest and potential adventures.
An expanded bestiary contains a host of strange creatures and servants of the Enemy, from the beasts of the forest to the fabled Great Spiders. Variant Cultural Backgrounds like River Hobbits or Wayward Elves offer new options for adventurers, while new Fellowship Phase actions bring the wild to life in your games.
Follow the Anduin river down from the chill springs of the Misty Mountains to the southern edge of the Wild! Explore the dread forest of Mirkwood, running from the lonely thickets of the north to the very gates of Dol Guldur! Enter the Heart of the Wild, and defend it against the rising Shadow.