What is a landowner's responsibility to habitat preservation? In the past, owning land meant arranging it for one's own use, but this in turn generally resulted in destroyed or degraded habitat. In today's world, loss of biodiversity has become a public concern. Does the landowner now have an obligation to manage his land differently? Can habitat protection be superimposed on a private landowner? Joseph Sax explores these questions in his lecture on the interconnections of ownership, property, and sustainability. This lecture was given on March 11, 2010, at the 15th annual symposium sponsored by the Wallace Stegner Center for Land, Resources and the Environment at the S. J. Quinney College of Law, University of Utah.