Nick Harkaway: Gnomon

Near-future Britain is a state in which citizens are constantly observed and democracy has reached a pinnacle of `transparency.` Every action is seen, every word is recorded and the System has access to thoughts and memories.
When suspected dissident Diana Hunter dies in custody, it marks the first time a citizen has been killed during an interrogation. Mielikki Neith, a trusted state inspector, is assigned to find out what went wrong. Immersing herself in neural recordings of the interrogation, what she finds isn`t Hunter but rather a panorama of characters within Hunter`s psyche.
Embedded in the memories of these impossible lives lies a code which Neith must decipher to find out what Hunter is hiding. The staggering consequences of what she finds will reverberate throughout the world....