Glorantha was first introduced to the wider world than Greg Stafford's circle of friends with the publication of the board game White Bear and Red Moon in 1975. The game featured a war between the Sartorites and the Lunar Empire in a region of Glorantha known as Dragon Pass.
Now Chasosium has taken us back to Dragon Pass (some of us never left) with the publication of the first book in the Lands of Runequest series. No doubt others will follow, and I'd guess Prax will be next.
The book has a history of the region and provides a gazeteer of Dragon Pass and some neighbouring regions including Tarsh and The Grazelands. There are regional maps and streetplans of some of the larger settlements, some sample 'typical' NPCs, details of some local cults, rules for creating additional types of PCs (newtlings anyone?), and additional bestiary entries providing details of creatures and other encounterable beings.
Different people would want different things from a book like this, but for me the level of detail feels about right. There's enough meat on the bones to give GMs plenty of ideas for adventures while leaving enough blank space for them to flesh out their own games.
The art and production values are glorious as is the norm with the current line of Runequest publications.
Nice.