What You Never Knew About Tubs, Toilets, and Showers by Patricia Lauber, illustrated by John Manders

From chapters.ca:
In the Middle Ages, St. Francis of Assisi listed dirtiness as a sign of holiness... But by the mid 1800s clean was in. The early Greeks and Romans were among the first to build public baths and toilets. One of the biggest Roman baths held three thousand people at once - and everyone went naked! But when those empires fell, so did the standard for cleanliness. It would be 1,400 years before bathing came back into style. Newbery Honor- wining author Patricia Lauber and artist John Manders team up again to tackle the dirty business of getting clean in their latest book, What You Never Knew About Tubs, Toilets, & Showers. In this hilarious how- to of bathing and bathrooms, readers can take a trip through the stalls of history and learn not only how bathrooms came to be, but who used them and why.