Girl 4 is, I believe, the first novel of author Will Carver and is a crime novel set in London - nothing unusual about that, but the way the book is written does set it out from the crowd in a sea of London based murder mystery books.
The plot itself revloves around a serial killer, his victims and the detective trying to bring him to justice. It explores the lives of each of these people and what happens to them in and around the crimes, including in many cases, descriptions of the deaths/murders from said characters own view point.
An unusual writing style - this book is written in the first person, from the point of view of various characters. Personally there were plus and downsides to this for me - on the one hand it was different to most other books and thus interesting and you got to connect better with the characters. On the other hand the further I got into the book the more I kept muddling up the girls and forgetting what had happened to which one.
There is a twist at the end which I wouldn't say was exactly shocking, but it's not one I would have guessed from the start (I did figure out the twist when it was first hinted at later on in the book) and it helps to keep you interested throughout, wanting to turn each page to see where it's going to go.
One thing that niggled me was the name of the detective - I'm sure it's just me, but I found 'January' to be a really irritating and silly name for a man, or anyone really (hope there is no one called January reading this).
Overall I felt the book was quite engrosing (enjoyed is probably the wrong term considering the subject matter) and after about 20 pages I got used to the writing style, making it quite a page turner, although I will admit that initially I did keep forgetting who was who as the narrative jumped from person to person. At under 350 pages long it isn't a long book and doesn't require a great degree of concentration to get through - I read my copy in the car (not while driving I might add) and in front of the TV.