Out of the Abyss
Volo's Guide to the Underdark
Given a moment to inspect this book, it looks like it was written by someone named Volothamp Geddarm. He apparently has written a number of references on monsters and regions of Faerun. This one, however, seems to be focused on the Underdark. How he came to survive while writing it or how it came to be printed, you have no idea.
The book is in relatively good shape, although it seems some sections are missing. Most interestingly, there is a map of the Underdark in this part of the world.
One aspect of this book is that it contains a map, something that could be invaluable for you in escaping the reach of the drow and returning to the surface world. You notice Velkenvylve on the map, the place where you were held as slaves by the drow. Yet, there is one problem: you are unsure of the orientation of the map. Which way is north, east, west or south?
Note: A bigger version of this map will be available in Fantasy Grounds.
There seem to be several entries on landmarks in the area. If you can find and correctly identify those landmarks, then you can orient yourself on the map. That seems a way forward.
Beyond that, there are entries for several locations that are relatively nearby, including: