The permaculture community mourns the loss of a brilliant writer and teacher, Toby Hemenway. The author of *Gaia's Garden* and *The Permaculture City* died Tuesday after an 18-month bout with cancer. If you don't have time for his excellent books (or even if you do!), check out this insightful 2012 essay about the paradigm-shifting nature of permaculture. With its in-depth discussion of the late-18th-century discovery of oxygen and Antoine Lavoisier's subsequent rocking of the scientific community, Hemenway explains that today's permaculture revolution resembles the revolution in chemistry which brought about a new way of thinking about the natural world. As science deniers are poised to take the helm in Washington, the time is now to brush up on the foundations of chemistry as well as on the roots of permaculture, namely, its nature-based approach to the design of human settlements.