The basic premise of the book is that God offers Lucifer a second chance if he can live one month as a human. Declan Gunn is depressed London novelist contemplating suicide so God puts his soul on ice for a month and Lucifer takes control. This is an at times hilariously funny novel as Lucifer immerses himself in the pleasures of the flesh. The descriptions of Lucifer's reactions to smelling the various odours that make up a walk through the London streets are particularly vivid. The ideas that Duncan raises in this novel are not new but the first person narrative helps to create a compelling portrait of a fallen angel, who may or may not be ready to return to the fold. My only criticism is that Duncan's prose is very dense and I had to stop reading at regular intervals in order to assimilate the events narrated.
I understand that a film of the novel is proposed, starring Daniel Craig as Lucifer and Ewan McGregor as Declan Gunn. I suspect that this is not an easy novel to adapt to the screen and I look forward to seeing the final film with interest.