I've always been a fan of the Doctor Who series. Lately more from a nostalgic point-of-view, because - face it - the series is mostly a bit childish. It is some of the novels that have sparked my interest again in Doctor Who. Yes, there are too many books and too many poor books. But there are some great ones and as far as Doctor Who novels go, you won't find many better novels than "The Turing Test".
The story is told from three different points-of-view: Turing, Greene and Heller. They're constantly questioning their loyalty, humanity, beliefs (and sanity). The Doctor is kept mysterious all along the way, as it should be.
This novel is about good & bad, trust & deceit. It is a mature novel, with stylish writing and good plotting.
"The Turing Test" doesn't make for a novel with a lot of action, but if you're looking for an intelligent, introspective story, this is the one you want to read.