This is a good book to read if you are interested in agriculture and how the discovery of phosphorus as a fertilizer changed the environment. The prairies were stripped of native grasses that resulted in the dust bowl and big farming industry. Runoff of excess phosphorus enters our lakes, rivers and streams causing green scum and harmful algae blooms that can deplete waterways of oxygen, cause fish kills, damage ecosystems or even result in “dead zones” in larger bodies of water.

I enjoy reading books that focus on a rabbit hole of STEM topics, especially when it's a topic I never stopped to consider before coming across the book. In this case the rabbit hole is phosphorus (who knew), and the author does an excellent job making it engaging and informative at the same time. Witness the excitement of discovery in 19th-century England as large phosphorus deposits are found and utilized to increase crop yield dramatically. Witness the subsequent capitalization and industrialization of the element, and witness the inevitable backlasgh of unintended consequences as the world moves towards a standardized, modern approach to raising its crops. What can we do to clean up the mess while still maintaining the crop yields we need to support ourselves?

The author didn't really answer that question, unfortunately. He wrapped the book up with a poetic conclusion that followed a quick overview of the misguided attempts of larege philanthropic organizations that only made things worse, which included a few hints at what would work but not how we'd get there. He also went down a rabbit hole within a rabbit hole, embedding the seeds of another book entirely when he covered the recent history of Australia's Nauru Island. None of that belonged in this book, and I suspect the author became too personally engaged in the human drama to edit it out. Sad as it is, that content detracted from the story of phosphorus by taking us on a long detour of human rights abuses on an island that just happened to be a former phosphorus mine.

To get a 5, the book would've need a little more focus at the end, and a clear recommendation on how to address the issue that the author identified. Nonetheless, I learned a lot and enjoyed doing so - this is a positive review of a book I recommend to others.