Equations of Life by Simon Morden
My rating: 4 of 5 stars
I read this because it was nominated for the Philip K. Dick award in 2012, and I'm glad it showed up on that list as I hadn't come across it in any other way. Technically the entire trilogy is nominated.
This is set in a post-apocalyptic London (in the "Metrozone"), in a time where bombs have destroyed most of the world and countries like Japan have completely disappeared due to environmental disaster (war-related).
Samuil Petrovitch is around 20, having recently escaped from St. Petersburg and working as a graduate physics student, when he ends up helping someone who is being kidnapped. He gets involved in a situation involving Russian mobsters, Yakuza, and ends up with technology going crazy.
The story is fast-paced and has a lot of bits to make my geeky heart happy, including mathematicians who might be cracking the code to time travel in the midst of the chaos, a main character who swears in Russian, a nun who just happens to have the biggest gun of anyone, and a new Japan created in a virtual space. Samuil is written to be complex, but the age of the characters really got to me - Maddy and Sam are both around 20 and I just kept thinking how much more I'd believe their actions and powers of deduction if they were at least in their 30s.
I think I may actually read the next book.