Every adventuring group needs a place to fence plundered goods and heal grievous wounds sustained during adventures. For the Spelljammer setting, a setting where players sail wooden ships through the fantasy equivalent of outer space, the Rock of Bral is the best they can hope for.
I have to confess that back in the day, my fourteen year old brain only scratched the surface of what the Spelljammer setting had to offer. It quickly devolved into Space Dungeon at times, using the setting as a way to have dungeons in asteroids. However, the Rock of Bral was something I quickly wrapped my head around.
The Rock of Bral is one of the most detailed fantasy settings in all of Dungeons and Dragons geekdom. The setting is detailed from it's early days as a mind flayer outpost, to a pirate headquarters, to a thriving fantasy city catering to all the needs in wildspace.
Due to the fantasy physics of the setting, both the topside and underside of the city are detailed. While the underside is little more than a prison, the topside is fleshed out to a fantastic degree, detailing the noble houses, the neighborhoods, the underbarons, and much more, giving the Dungeon Master everything he needs to run a long campaign without the PCs ever leaving the confines of the city.
So much better than anything to come out for 5e. Back in the days when D&D made real worlds, fleshed them out but left plenty for the imagination to fill in between.
Information on the city, the political factions, the shopping, the lifestyles, major NPCs, all the while detailing where you can easily fit your own ideas without disrupting the base city at all. Of course any DM is perfectly capable of scrapping the whole thing and starting fresh, but it's nice to have a framework to start from -- again, something that 5e is woefully neglectful of.
As I said in my Practical Planetology review... I'm prepping for a 5th ed campaign, and I'm re-reading these supplements.
Maps; great. Plots and schemes; great. Info on the rock in general; great.
NPCs; too goddamn many. Seriously. There are just too many in this book.
That being said, the book makes Bral a highly desirably place to set a campaign, or at least use as a location, and that's what I'll be doing. Classic Spelljammers.