A book about the principles of designing good natural spaces — parks, yards, gardens, trails, etc. — as well as how to make good maps and how to involve stakeholders in a productive way. The chapters are organized (very smartly) based on the notion of patterns, as popularized in Christopher Alexander's masterwork, "A Pattern Language".
The book is informed by decades of the authors' research into the ways that humans are attracted to nature, as well as other human characteristics, but it is written in plain and concise language.
Overall: this is a brilliant, brilliant book, and it's a shame that it seems to be obscure and out-of-print. I hope that changes over time. It's also unintentionally one of the best books about video game level design ever written.