Mary Ellen Hannibal's books include The Spine of the Continent: The Race to Save America's Last, Best Wilderness. Her most recent book, Citizen Scientist: Searching for Heroes and Hope in an Age of Extinction, was named a best book of the year by the San Francisco Chronicle and won a Nautilus book award. A frequent speaker, she performed a Stanford TEDx talk in 2017 and her “big” TED talk, on butterflies, the human soul, and citizen science, was released in 2020.