There is a whole book for explaining Eberron for use in a campaign, but where can I find a similar explanation for the Forgotten Realms? There are little bits of information sprinkled into the Player's Handbook and the Dungeon Master's Guide when something about the Forgotten Realms is relevant (such as an aspect of a playable race's culture), but is there some book I can read where everything I'd need to know about the Forgotten Realms is compiled in one spot?
SCAG is good to start, but the main thing with Forgotten Realms is it's so old and has so much history (It actually existed before Dungeons & Dragons) that lore is spread all over several editions of D&D, novels, adventures, modules, video games and it's constantly changing just a little with each new thing released and with each individual campaign run within it. It's constantly expanding and what one person knows for sure happened in Waterdeep may not be what someone else knows happened there.
As the others have said those have current info for 5e, for general lore just searching online. There have been forgotten realms compendiums published in the past. I had one in the early 90's. If you are strictly looking for something as reference and a lore guide up to whenever it was published you may be able to find one somewhere. Of course it wont have the most current lore and stats would have to be converted.
There is a whole book for explaining Eberron for use in a campaign, but where can I find a similar explanation for the Forgotten Realms? There are little bits of information sprinkled into the Player's Handbook and the Dungeon Master's Guide when something about the Forgotten Realms is relevant (such as an aspect of a playable race's culture), but is there some book I can read where everything I'd need to know about the Forgotten Realms is compiled in one spot?
There is the Sword Coast Adventurer's Guide. It is not as voluminous as the Eberron book, though.
SCAG is good to start, but the main thing with Forgotten Realms is it's so old and has so much history (It actually existed before Dungeons & Dragons) that lore is spread all over several editions of D&D, novels, adventures, modules, video games and it's constantly changing just a little with each new thing released and with each individual campaign run within it. It's constantly expanding and what one person knows for sure happened in Waterdeep may not be what someone else knows happened there.
As the others have said those have current info for 5e, for general lore just searching online. There have been forgotten realms compendiums published in the past. I had one in the early 90's. If you are strictly looking for something as reference and a lore guide up to whenever it was published you may be able to find one somewhere. Of course it wont have the most current lore and stats would have to be converted.
That's what happens when you wear a helmet your whole life!
My house rules