Peter Harnik is the founder of the Center for City Park Excellence at the Trust for Public Land, which he directed until his retirement in 2016. Previous to Urban Green,  he authored Inside City Parks, a book about the park and recreation systems of the 25 largest U.S. cities. He was co-creator of the ParkScore methodology of rating urban park systems across the nation and co-founder of City Parks Alliance. Previous to TPL, he was co-founder of the Rails-to-Trails Conservancy and coordinator of Environmental Action, Inc. He is currently writing a history of the rails-to-trails movement in the United States.