It's urban fantasy, and our protagonist is an angel called Bobby Dollar - he's an Advocate, an angel who lives & works on Earth. When a person dies they are judged by a higher angel who decides if they're going to Heaven (perhaps via Purgatory) or Hell, and there's an Advocate from Heaven and a Prosecutor from Hell who argue and present the case for each side. Very much like in a modern legal case. Advocates live in real bodies in the real world, despite being angels, and only go up to Heaven to meet with their supervisors. So in many ways Dollar is just like a normal person in the normal world, except for his job is that he gets called up and told where a death is and then he drives to it and steps out of time to argue the case for Heaven. When he's not working he hangs out in a bar with his fellow angels.
Trouble starts when Dollar shows up to a job, but the soul of the deceased is missing. Then the Prosecutor from that case is found dead in a gruesome (and unusually permanent) fashion, everyone thinks Dollar has something belonging to a Duke of Hell, and more souls are going missing. There's also a rookie Advocate, who seems more important than he should be, oh, and there's a stunningly beautiful demon that it would be suicidal for Dollar to fall in love with, but of course he does. Quite possibly there'll be a love triangle thing going on in the later books, because there's also an angel (another Advocate) that Dollar has a thing for/with. The story kept me sucked into it, wanting to know what happened next, with a Chandler-esque atmosphere to some of it. But then somehow the ending disappointed me. Presumably all the interesting questions are going to be resolved in the last book, because there was just one bit that got dealt with here. And yet I wasn't left thinking "can't wait for the next book!". I'm not sure why, though.
I did like the way Heaven was portrayed, that has the potential to be interesting if it is actually important to the plot rather than just background. Although the mythology of the book is very much (Catholic) Christian in nature it's explicitly made clear that this might not be the case throughout the afterlife, that this might be the way it's represented to this batch of angels and demons because that's their cultural mythology - Dollar has never met the Highest and knows of no angel however exalted who has, he's just a small piece of a large machine. None of the souls in Heaven, angels or not, remember who they were in life - they're completely wiped clean of memories. And everyone is cheerful and unquestioningly happy. Dollar knows (or rather has been told) he was once alive on Earth, but he remembers nothing before the 90s when he became an angel. It's clear the happiness in Heaven is externally imposed, too, Dollar mentions resisting it when he goes to report to his supervisor and he talks about having to concentrate to keep questioning things rather than just cheerfully accepting them. And that's all very creepy. Particularly as demons remember their previous lives (or at least the impossibly beautiful Countess of Cold Hands does, or says she does). Hell is clearly bad, and demons are demonic, but Heaven is all a bit Stepford Wives.