'I return to Paris in five days. Stop washing.' So wrote Napoleon to Josephine in an age when body odour was considered an aphrodisiac. In stark contrast, the Romans used to bath for hours each day. Ashenburg's investigation of history's ambivalence towards personal hygiene takes her through plague-ridden streets, hospitals and battlefields. From the bizarre prescriptions of doctors to the eccentricities of famous bathers, she presents us with all the twists and turns that have led us to our own, arbitrary notion of 'clean'.