This thick volume is filled with numerous details on the planar experiments the Arcane Brotherhood has been performing, at the request of Archmage Arklem Greeth.
Most of the entries go into exhaustive detail. It seems the wizards have 'attuned' several portals to the abysmal and hellish planes, attempting to research the eternal Blood War being carried on by the demons and devils.
Supreme among the creator races were the dragons, powerful enough to raid large cities of the other creator races with impunity. Dragons dominated the surface world, claiming cast areas of territory and battling each other for land, mates and status. The great drakes only suffered setbacks when lesser races mastered magic, and they remain influential today despite the advances of such rabble.
No conclusion seems to have been drawn, but it is pointed out in several places that one curious property of the portals is that their attunement is easily disrupted by material of the opposing planes. One wizard warns that trying to actually send material from one plane through the wrong portal could be highly destructive.