I imagine it's an enjoyable read as a stand alone book, but there's some spectacular character development that will mean more to you with the background.
Generally, for those who aren't familiar, the main character October Daye (Toby) is a changeling PI in modern times San Francisco (and the surrounding bay area). I'm not well versed in the legends of fae, but the mix with the modern non-fae world has some interesting twists.
The book begins with action, and quickly moves into a thrilling and intriguing adventure. As mentioned before some familiar faces make tantalizing and developmental appearances. I particularly enjoyed the further exploration of the Luidaeg and Tybalt. The further development of Quentin, Luna, and Raysel was fascinating.
I did notice one or two continuity issues, but they were small, and irrelevant to the overall story.
The plot explored a new world to me, and while the mystery was obviously providing an increased tension to the story there was never a point at which I felt more lost or confused than Toby.
I'm not generally an emotional reader, I can definitely be taken away by a story, but this is the first time I remember crying while reading. As a caveat I am pregnant, and I'm told that while pregnant I'm more inclined to such things. (It was late in the book, so I'm not going to tell you where it hit).
I thoroughly enjoyed the book, and look forward to Late Eclipses (they include a tantalizing tid bit from the next one at the end of the book, and I'm resisting the urge to read it; I did when I finished A Local Habitation, and it made it harder to wait).
I knew when Groblek brought home the book that I was going to enjoy it and I was still surprised by how much I couldn't put it down.
If you're interested you can find more details here:
http://www.seananmcguire.com/
The Avid Reader in Davis had An Artificial Night on the shelf, and any local book store should be happy to order for you.
I also enjoy Seanan's music, and Feed, under the pseudonym Myra Grant.