This boxed set accessory for campaign and character development contains information of the "organisms and their surroundings" for the Forgotten Realms world of Faerun.
From the back of the box:
Within this box are nine booklets. Eight of them, each written by an expert in the area, describe various ecological niches on the continent of Faerun.
Begin by reading the Explorer's Manuals, which:
-introduces the reader to the organization of the eight area-specific booklets.
-contains the whole of the above excerpt from Elminster's work-in-progress about Realmsian biodiversity
-provides color-coded encounter tables for the eight other booklets, along with instructions for their use.