Comment from Jon Courtenay Grimwood:

Light is the kind of novel other writers read and think: "Why don't I just give up and go home?" That was certainly my first reaction on reading its mix of coldly perfect prose and attractively twisted insanity. It's also the only book to bring me unpleasantly close to sympathising with a serial killer. But this is M John Harrison: so antihero Michael Kearney is a mathematically brilliant, dice-throwing, reality-changing hyper-intelligent serial killer haunted by a horse-skulled personal demon.

Harrison's genius is to tie Kearney's narrative thread to those of Seria Mau – a far-future girl existing in harmony with White Cat, her spaceship, surfing a part of the galaxy known as the Kefahuchi Tract – and Chinese Ed, a sleazy if likeable cyberpunky chancer with a passion for virtual sex.

This is not a kind book, or even a particularly likeable book. But then I suspected it was never intended to be, and the author wouldn't want the kind of people who want to like characters as his readers anyway. What it is is stunningly written, meticulously plotted, hallucinogenically realised and brutally honest. No one who reads it could doubt that Harrison might win the Booker if he could be bothered.

Light is also the book that novelist and critic Adam Roberts was so sure would win the Arthur C Clarke award, he offered to change his name to Adam Van Hoogenroberts if it didn't. We're still waiting . . .