By Light Alone
Adam Roberts
Gollancz, 2011
Hb, pp416, £18.99
ISBN 9780575083646

By Light Alone is one of those books in which the author has concerns about modern society and extrapolates from these to create a world in which all his worst fears have come to pass: a warning to us all to change our ways.
On Roberts’s future Earth, a bug has been invented which allows people to feed by absorbing the energy of sunlight through their hair. Unfortunately, rather than saving mankind from the conflict between a growing population and dwindling resources, it has exaggerated the class divide: the rich wear their hair short and eat food to show off; the poor loll in the sun all day.