If you are a fan of the urban fantasy detective, I highly recommend you read Thicker Than Water, one of the best Felix Castor books to date. Reading prior books is not required; while they add some character back story and add to the overarching philosophical developments, the plot is largely discrete in each book and Carey does a nice job of providing information without backstory infodumps. Thicker starts off with a teaser, a third person witnessing of Castor's demon-ridden friend Rafi being abducted from the asylum right before the scary Dr. Mulbridge comes to take him to her special house of horrors scientific research. It moves quickly into a confrontation with the police when Castor's name is found scrawled at a bloody assault scene. Like all decent fictional PIs, Castor is not content to let the police investigate, suspecting the victim was directing attention to his special exorcist skills, and soon finds himself poking around one of London's rougher estates (which seem to resemble inner city projects for Americans).Carey does a particularly nice job world-building, using modern London as his base. His take on the supernatural is largely spirit-based, with ghosts (leftover human spirits), zombies ("corporally-challenged" spirits), loup-garou (animal bodies taken over by spirits), and demons, the big bad unknown. Thicker delves even deeper into the metaphysical underpinnings of ghosts and demons as Fix investigates the spiritual miasma at the estate. He does a very nice job realizing the various manifesting ghosts and Fix's interaction with them, truly building an experience that seems plausible. The scenes of Fix visiting a hospital were especially outstanding.I enjoy many of the supporting cast, especially Nicky, the paranoid hacker zombie (and don't you just love a review where you get to type that phrase?). He is the information gatherer for Fix, a somewhat standard supporting character role, but his breath-challenged status was a stroke of genius. His dialogue is always enjoyable, but he had me chuckling at "What highlights? He's born, he lives, he maybe dies. Bit of a cliffhanger ending there, but that's as good as it gets." Juliet the succubi continues to evolve. This time Carey nicely treads the balance between drooling and scary, and still manages to make her seem real. Her limited emotional range is clear, as is the ways she is humanizing. Nicky treats Fix and Juliet to a Blade Runner screening. "'What did you think of the movie?' 'I enjoyed the deaths,' she said, like someone looking around your living room for something to compliment you on and finally settling on the curtains because all of the furniture is eye-wateringly bad."Despite the charm of Nicky and Juliet, this is the first book where I liked Fix more than the ensemble; perhaps that is a staple of the UF detective field--the friends are often more likeable than the detectives, who uniformly seem to be ill-tempered and emotionally immature.I generally enjoyed the generally sophisticated writing style, with the exception of the occasional awkwardness. I'm unsure if some of it is perhaps a particularly English way of speaking, local idioms or just perfectly executed English language that caught me, being somewhat grammar-challenged. Examples include, "But she's always fought shy of explaining how that other life works," "I looked forward cordially to never finding out," and, "I had things to do over there that I didn't want the daylight to look upon." Still, the writing was tempered with enough world-building, character development and humor that such stumbles were quickly left behind. I wholeheartedly recommend it for UF detective fans. One of the tops in the field.