Threshold Book

The second book in the Boundary series, Threshold follows the continuing adventures of the Ares space exploration company in its attempt to find and document the secret ancient bases left over from a war among alien races in our solar system. This particular adventure focuses on the settlement of a new base on Ceres and some industrial espionage between the existing space explorers and a new ship launched by the European Union. Adventure ensues!

A few thoughts:

Threshold walks a fine line between space opera and hard science-fiction exploration story. It spends a lot of time thinking about how the settlement of the solar system might work, pondering the international politics of space exploration, considering how different countries might tangle with the problem in their own ways. But it also lets that stuff rest when a judicious use of internecine struggle or dramatic space adventures are needed.
After the first half, the book gets pretty engrossing, with the villains set up in such a way that we can easily despise them and will greedily read forward in anticipation of their downfall. It's not unlike a Dan Brown book in that way, though Brown is much better at crafting the perfect little chapter that drives you to read the next one.
At the same time, the characters are pretty hollow, without the individuation you might hope for from a stronger writer. Our heroes are all unbelievably smart and pretty lucky. Of course, such characters are very satisfying in a space opera; it would be a sad, dark story if Peter Watts had written it, for instance.
The outer space exploration Flint and Spoor bring to the story are great, particularly the different planetoids the heroes visit. The description of Jupiter's moon IO, for instance, is particularly harrowing.
I like the sprinkling of proposed technologies, particularly the notion that they're seeded by our interactions with alien technologies left over in old bases. The nanotech "Dust" is a bit extreme in its capabilities, but the rest of it works well.

A sunny bonus: it turns out the publisher of this book, Baen, has a free library of ebooks for the sampling, like a drug dealer. Seeing Baen's ebook publishing policy, I'm definitely inclined to give them more of my business. Enjoy them!