This note contains spoilers for the book.

By Eric Flint and Ryk E. Spoor. I'm kind of assuming that it's mostly by Spoor. Since I interact with him regularly online, I should mention that I don't recall him saying that.

This is a far-ranging near-future SF novel, involving the sciences of paleontology, remote sensing, and rocket engineering. At least. It also involves politics and national security, and of course humans. We start with the discovery of Bemmius Secordia right on the Cretacious boundary layer. It's in a death scene with many period predators, which seem to have been killed by small holes through their bones that just match the size of some ceramic spheres found in the fossils. This connects remarkably cleanly to many of the people involved working for the Ares corporation, working with NASA to get some Mars probes going.

The probe finds an alien base on Phobos, and a mummified Bemmius. The people involved in that end up, eventually, on Phobos and then on Mars, where they find the alien bases. We don't get to any technology we can learn from the aliens, though there is a second book (which I have on paper, I've just started it). However, they got here, which is suggestive, and the materials their stations are made of seem to suggest some differences in tech abilities.

I like the characters, too. There's some real variety, and they're all of interest. No serious bad guys, either. And in fact there isn't much character conflict, this is people against the universe, not people against people. I like that, at least some of the time.