Quiddity means what? It means the essential nature of something, from the latin 'quid' meaning 'what'. And 'What?' was the first word that crossed my mind when I heard something heavy drop through my letterbox one morning. This book was the what - courtesy Sam Mills herself, who sent me a copy as a reward for slagging off Nick Clegg on Twitter. I was delighted because this was one of those books that make my eyes light up the moment I hear about them. So, I hear you ask, it's about what?What connects a young man who finds the body of Will Self in 2006 and a lesbian book reviewer in 2049? The WSC that's what. A literary cult devoted to Will Self towards which they are both drawn, along with its shadowy leader Jamie Curren, author of How Will Self Can Change Your Life.As the young man, Richard Smith, explores Self's body of work he becomes more and more obsessed - possessed even - by the sesquipedalian genius of the real Will Self, whose physical body it was not. The murdered 'Will Self' from part one haunts the real Will Self in part two, while in part three Richard is imprisoned in a tower block writing The Diary of a Murderer under the care? of a psychiatrist called Professor Self (no relation) who is experimenting with some literary potions.Mia, the lesbian book reviewer, receives a mysterious package containing Richard's diary, that sets her on the trail of the WSC in part four and last, but not least, in part five we meet my favourite character: 'the author' 'Sam Mills' - who reminded me a little of Timothy Cavendish in David Mitchell's Cloud Atlas, not least because both are literally (and literarily) laugh-out-loud funny. He - for he is a he, unlike our author who is a she - has written a book called, yes, you've guessed it: The Quiddity of Will Self - the literary equivalent of Being John Malkovich which, he explains to the real Will Self in a letter, "aims to be a bizarre comedy, a murder mystery and a sincere homage to you and your work".Obviously there's some sex and drugs along the way.Quirky and distinctly contortuplicated, this novel is so tricksy it comes up behind you, taps you on your right shoulder, then whispers "boo!" into your left ear, while wearing sinister masks on each of several scary faces. Full of words that jangle in your head, The Quiddity of Will Self is a dangerous odyssey through a cloudy mind - but whose? I'm not even sure how many Will Self's there were. I just hope the paranoia that pervades this novel isn't infectious.Why are you looking at me like that?What?