HBO Documentary Films and the National Institute on Aging of the National Institutes of Health ... present ; executive producers, Sheila Nevins, Maria Shriver ; series producer, John Hoffman
a NOVA production by Big House Productions for WGBH Boston ; executive producer, Chris Schmidt ; co-produced by Cara Feinberg ; written, produced and directed by Daniel McCabe
a Nova/WGBH, La Cinquième, Südwestrundfunk, Gedéon Programmes, Meridian, and NHK co-production ; produced for Nova by Providence Pictures, Inc. for WGBH/Boston ; written and directed by Liesl Clark
A production of Clearwater Documentary Inc. ; produced in association with Canadian Broadcasting Corporation ; The Nature of Things ; Directed and written by Tom Radford, Niobe Thompson ; produced by Niobe Thompson
presented by Thirteen for WNET.ORG ; Distributed by American Public Television ; A ParnassusWorks Film ; produced and directed by Richard Rifkind, Carole Rifkind