Sewer is another book in the Object Lessons series, exploring sewers as they impact our daily lives though mostly unseen and considering what we should do to improve them for the future. Rather than focusing just on the physical sewers, the book also looks a lot at blockages like fatbergs and wet wipes and considers what human consumption and use does to these practical structures.

The Object Lessons series is always, as far as I've seen from the ones I've read, interesting in some way, with each book taking a particular direction with the object in question. Though Sewer cites Robert Macfarlane's Underland, this book doesn't take that approach of focusing on the physical underground spaces in our imaginations and reality, but considers sewers in their sanitation purpose and what happens when they are blocked, both in terms of the people who work in them and what it is that causes those blockages. Not necessarily a particularly savoury topic for a book, but it was certainly something different and it's useful for thinking about what you personally put down the drain and how your actions are part of a collective whole (which is basically the message of the book).