Justina Robson 
Switch 

This groundbreaking new novel from one of the genre’s most respected authors is a thrilling mix of science, magic and politics.In Harmony, only model citizens are welcome.A perfect society must be maintained. The defective must be eradicated. For orphans like Nico and Twostar, this means a life that’s brutal, regulated and short. But Nico and Twostar are survivors, and when they’re offered a way out of the slums, they take it. Unfortunately, no one told Nico the deal included being sentenced to death for the murder of one of Harmony’s most notorious gang leaders.Or that to gain his freedom, first he must lose his mind.