Starting this tonight. As a matter of full disclosure, I love the game, and was inspired to read most of the other Halo universe novels and - more importantly - the Ringworld books by Larry Nevin, though the two have no connection except for one rather obvious similarity. Thank you Bungie and microsoft.

++Update++

Cryptum was interesting, but not nearly as "alien" as I had hoped. Written with a very tight point-of-view from a single narrator, I admit that I'm a little disappointed. In the game, you get tiny hints of what the Forerunners are like, so the imagination is allowed to run wild.

While the narrator is interesting and the plot maintains a good pace, I just wanted to like this more than I did. Cryptum is not a wide epic like Dune or the Foundation series where you are introduced to a huge and diverse universe with big concepts and intricate subplots. Instead, you get an almost provincial and feudal uniformity where whole races can be summarized in a few sentences. I wanted a wide-angle lens, but received a pin-hole camera instead.

I do plan to finish the series, though.