This was equally interesting and depressing. I'd heard a lot of buzz about this several years ago when I believe there was a movie coming out, which initially piqued my interest. It details a depressing life of a police agent working undercover as a drug addict in a drug den, but subsequently becomes addicted to drugs in the process. Side effects of this drug include psychotic breaks that lead to him being unable to distinguish reality from hallucination. I found the overall story to be sadly realistic in the way that addicts are both criminalized but also used as tools in the legal system only to be discarded when they have no more utility. The twists were interesting and unexpected, but some of the logic fails when you take a moment to think about it. For example, this seems to be a pretty technologically advanced setting with scramble suits and the ability to hide advanced monitoring software, but for some reason there is still a reliance on getting police officers addicted to drugs in order to infiltrate crime circles. Like.. surely there's a better way. The characters weren't as fleshed out as much as I would have hoped and were honestly just used as props to move the story forward, but there were times when characters did bring a sense of charming realism to a scene or two. Overall, this book was fine. Quick read, but nothing to write home about in my opinion.