A novel strongly based on the facts surrounding the Big Problem of clean water for London in the 1840s, and the cholera epidemics at the time. Matthew Kneale is steeped in the history of the time and wears his learning lightly. His solemn and slightly Pooterish hero, Joshua Jeavons, who is our narrator, makes the book amusing and a page turner. Aspects of the plot, his search for his missing wife for instance, were less interesting than his account of his search to impress his plans for sewage solutions on a reluctant world. It was a book that I was glad to read: I learnt quite a lot, and felt part of a deeply unpleasant London, its smells and sights. Not entirely convinced by the ending. Hmmm. It struck the only false note. ( )