Samuil Petrovich, the unlikely hero of Equations of Life, begins this novel by creating artificial gravity. At some point between Equations of Life and Theories of Flight, Petrovich married Madeleine who, when we last saw her, was a gun-toting nun. Madeleine apparently had a crisis of faith; she's now a gun-toting sergeant in the militia that is guarding the Metrozone from Outzone intruders -- including, evidently, Madeleine's own mother, who shoots Madeleine early on in the novel. Other key players who survived Equations (including Marchenkho, Sonja, and Chain) return in this one, although in lesser roles, and a couple of interesting new characters are introduced. The New Machine Jihad is also back, albeit in a somewhat different form. The plot involves Petrovich's more-or-less single-handed effort to prevent the "Outies" from invading the Metrozone.
Theories of Flight fleshes out the post-Armageddon world of Simon Morden's creation. The Metrozone (what's left of London, also called the Inzone) is shrinking; its residents are in danger of losing their relatively privileged lifestyles to the uncouth Outies who seek a share of the pie, or perhaps just want to stomp on the pie (sounds like class warfare, doesn't it?). The Outzone is expanding, encroaching on the Inzone; the Outies have devolved during the two decades since Armageddon, losing their culture and their language skills. Across the Atlantic, in Reconstruction America, cultural conservatism prevails: "you can't book even a twin room without a copy of your marriage certificate." (I've gotten used to the ever-so-sophisticated British portraying us Yanks as a bunch of hicks, and perhaps we deserve it, but the notion that Armageddon will cause Americans to forego premarital pleasure seems a bit farfetched.) Speaking of America's demons, let's not forget the CIA, which in Morden's future is still playing dirty tricks on the rest of the world.
In some respects the second novel is better than the first; in others it is not as good. I like that Morden seemed to be taking the story a bit more seriously; Theories of Flight isn't as outlandishly tongue-in-cheek as the first novel (losing the fighting nun concept was, I think, a good move). On the other hand, Theories seems less focused, less driven, than Equations. There's a lot going on in Equations (perhaps a bit too much), while an extended section of Theories feels like the literary equivalent of a movie chase scene -- or perhaps an intelligent version of the movie 300. It isn't boring; on the other hand, it doesn't keep the brain buzzing like Equations did.
A second complaint is that the AI advising Petrovich is intent on debating Petrovich's love life with him (does he love Madeleine or doesn't he?) -- an ongoing conversation that just doesn't work. A third is that Madeleine's near-fatal encounter with her mother seems like a significant plot point, but it isn't developed. Maybe Morden will tell us the rest of the story in the next book. Finally, while I like Petrovich's opinionated, sarcastic, antagonistic nature, there were times when the action came to a halt so that he could deliver one of his passionate lectures. Inspiring as they may be, a bit less of that would have helped the story maintain its momentum.
The concluding chapters wrap up the main story nicely but the short last chapter is an information dump. The world undergoes dramatic change in this novel. I hope the next one gives us a closer look at the messy political situation Petrovich manages to create.
If you enjoyed Equations, I think you'll like Theories, even if it lacks some of the first novel's virtues. Theories starts well, the middle is action-filled but light on substance, and the ending carries enough promise that I'm looking forward to reading the trilogy's conclusion. I would give Theories of Flight 3 1/2 stars if Amazon made that option available.