This is the hidden history of an invention that we use every day but seldom dare to speak of. In medieval China it was cutting-edge technology. For 19th-century Americans it was a newfangled alternative to dried corncobs and the Sears & Roebuck catalogue. Wits in Georgian London preferred pages of bad poetry. The sages of ancient Athens were content to wield the xylospongion instead. It's the tale of toilet paper; the biography of bumfodder. From its origins at the Imperial court of Emperor Hongwu to its reinvention as a quack remedy for haemorrhoids in 1870s New York city; from the Dutch and their mussel-shells to Henry VIII and his Groom of the Stool; from Madame de Prie's pioneering bidet to the space-age Washlet; from leaf-wielding chimpanzees to Mr Thirsty Fiber and the world's first three-adjective loo-roll – it's a story of necessity and invention, luxury and squalor, experiment and tradition. What does a submarine crew do when it runs out of toilet paper? Who...