In 2005, he published Planetwalker: How to Change Your World One Step at a Time (later republished by the National Geographic Society as Planetwalker: 17 Years of Silence, 22 Years of Walking).
He published Planetwalker: A Guide to Making a Difference in Your Community One Small Action at a Time in 2005, which was later re-released by the National Geographic Society as Planetwalker: 17 Years of Reflection, 22 Years of Walking.