As a new FR DM, I really have to ask why?
I mean, good grief, I've got, what 4 complete campaigns, nope, 5 in print set in the Sword Coast. I have enough material for YEARS if I want to use it. As a new FR DM, I don't even know what a Turmish is. Never heard of it and don't care. I know what a Kara Tur is, because I've been around for a while, but, again, don't care. The Sword Coast is ENORMOUS. It's about the same size as Greyhawk, I think. Why would I care in the slightest about other parts of the setting?
Just no, Greyhawk is a setting (and the name of the city in it), the world being called Oerth, which is much, much bigger then Swordcoast.
The Swordcoast is big, but there isn't much in it, and outside of a couple cities and islands, it's not that interesting.
Turmish is the only large democracy in FR, and one of the few black human majority populations in Faerun. They are the homeland of one of the major factions, the Emerald Enclave.
And the fact that you don't understand why you should care about their other regions of FR, is exact WHY you need a book like this.