The dedication to Hari Kunzru’s third novel is cryptic. It says: ‘To all at 34.’ Is Kunzru (who I guess is that age or thereabouts) offering fraternal solidarity to his contemporaries? Is he alluding to a smart bar with a numerical name? To the inhabitants of a shared house in which he once lived? Or, perhaps, to the code number for a cell of revolutionary terrorists? My Revolutions is just the sort of book to make you wonder.