by Paul Devlin ; directed, edited, and produced by Paul Devlin ; produced by Claire Missanelli ; a Paul Devlin production in association with BBC, YLE/FST Finland, Discovery Channel Canada, SVT/Sweden
a Nova production by Green Umbrella Ltd. for WGBH/Boston in association with BBC-TV and Sveriges Television ; produced by Peter Jones and Thomas Levenson ; written by Thomas Levenson ; directed by Peter Jones
a Quest Productions and Kikim Media production for Nova ; in association with the Catticus Corporation ; WGBH Educational Foundation ; senior series producer, Melanie Wallace ; produced and directed by Michael Schwarz and Bill Jersey