Expansive, in scope and in reach. This book may not suit those looking for a nice story, one that is usually sought in fantasy, but for those who want to delve deep in the mysteries of Middle-Earth, and those to whom the history of events described in Lord of the Rings excite to no end.
For those who are willing to brave through the avalanche of information to the very end.
And yes, very dark. It lays bare the thoughts which are too true in the real world itself: Men are not without failings, and with power and wealth, those failings catch them, and bade their fall. Which is only very true.