It is the direct sequel/continuation of 6 Sacred Stones, but that itself is the sequel/continuation of 7 Ancient Wonders albeit with some years passing between events (which do get partially filled in) - so really, its the 3rd and final(?) part of the trilogy.
Anyway, 6 Sacred Stones left me hanging, or should that be falling, so I am stoked that the wait is over.
I have only jumped back in, so cannot review from a complete book angle, but, so far, so good, and I'm braced for the ride to continue!
If you have no idea who Jack West is, recommend you start at Seven Ancient Wonders, then Six Sacred Stones, then this one.
Um, Sky Monster rocks! Someone turn this trilogy into film - Pete Jackson, when you have a spare moment dude.....
And Matthew Reily - I have read all his books (except the kids one he done) - pick ANY of them and you are in for a blast. Some of his books are linked by characters and events, so recommend starting from the oldest ones first to get the most from them - though unlike 7 Ancient/6 Sacred/5 Greatest, not essential.