Actually its very hard to describe contract in one word. The main premise itself is nothing new; the life of a contract killer who has Issues(tm).
But that's about as typical as it gets, the rest of the premise is; a...girlfiend?... who may or may not be reporting his activities to the police, his new boss who may or may not be an angel (yeah literally) and his victims who may or may not be coming back to life.
I can see that the ambiguous nature of this book has really annoyed some other reviewers and, while there certainly are some plot threads left dangling and some questions left unanswered, i will say that the majority of of them are satisfyingly dealt with - IF you pay close attention. Especially to Sally's dairy.
The next big gripe seems to be Spurriers odd writing style. It was certainly the first time i had ever read anything like it and after a few seconds of confussion i decided i loved it. Its probably best to click on Look Inside and decide for yourself wether you like it or not.
However even if you do like the writing style then the constant repetition of certain phrases will almost definitely get annoying towards the end of the book. Especially as everything else in the book is starting to get more and more annoyingly surreal.
Yet the best thing about this book is the gritty realism. Spurrier refuses to sugar coat, or hold back, on anything. The swearing is frequent, obscene and stunningly creative. As are the descriptions of peoples brains being blown out of their skulls. As are the worryingly well researched descriptions for building your own silencer, laundering your dirty money, etc.
It would also be criminal of me to neglect mentioning the fact that this book is often side-splittingly hilarious - just so long as you don't mind some very dark black-humour.