This is a massive collection of Glorantha Goodness, it revises the cults from the previous edition and brings them in line with new MRQII rule set.
It goes into further depth into the cult and pantheon mythos giving a bit more meat to help you portray your character.
It really goes to town on the Draconic, Storm, Solar, and Malkion Pantheons - all are excellently detailed and give a good feel for the culture.
I would have prefered it if the Nomad, Pentian/horse Nomad, Pamaltelan, and beast cults had been seperated out into distinct Pantheon/Traditions rather than lumping them together... still its only a minor point of preference.
Not all the cults from the previous editions made it to the book... and some of the cults/paths mentioned in the Glorantha Core Book don't get a mentioned inside so the cultures remain unplayable unless your predispossed to make some cults up yourself until they fill the gaps, inparticular Teshnos, East Isle, Pamaltelan and the Chaos Pantheon.
There are some minor error- missing spells, but hat said, this is a remarkable book, it makes the cults of Prax feel a bit lightweight.
[5 of 5 Stars!]