Unknown (film tie-in) by Didier van Cauwelaert Penguin, HK$104

There are many reasons you may want to read Unknown by Didier van Cauwelaert. You may have been lured here by Liam Neeson, who is starring in the movie adaptation. You may have read the story already under its original title - the superior but uncinematic Out of My Head - and not realised this isn't a different novel. Or you may be French and a fan of van Cauwelaert's other books and musicals - including Hors de Moi, the original title for Out of My Head which is the original title for Unknown (or Sans Identite en Francais). How many titles does one book need? The set-up is intriguing enough. Martin Harris is a Yale academic in Paris for a conference. After a car crash, Harris comes to, then goes home only to find his wife (Liz) doesn't have the first idea who he is. She is also living with another man calling himself Martin Harris who she believes is her husband. But all proof of the first Martin Harris' identity has gone missing. Three questions spring from this premise: what happened, why, and can Martin Harris 1.0 affect what happens next? Unknown is clever and twisty, if utterly ridiculous. In short: it should make a great movie.