Regional Plan Association mourns the passing of David Johnson, a former staff member and chronicler of RPA’s history. His 1996 book, “Planning the Great Metropolis: The 1929 Regional Plan of New York and Its Environs,” is the definitive history of the founding of RPA and a resource for everyone concerned with metropolitan regions. We were thrilled to host David at RPA last spring and talk with him about the changes in regional planning over a century. He was a vital resource for RPA’s centennial exhibition, The Constant Future, and a friend to anyone who cared about the tri-state region. We will miss his knowledge, optimism and enthusiasm, and are grateful for his lifetime body of work.