Brady Barr Herpetologist, Television Personality Through tales of his extensive work with alligators, snakes, and other reptiles, Barr shares his passion for science and firsthand observations of a planet in peril.

David Doubilet Underwater Photographer Having shot nearly 70 stories for National Geographic, Doubilet swims alone. He has introduced a generation to the wonder of the world's oceans.

Sylvia Earle Marine Biologist This world-renowned marine biologist describes the ocean as the cornerstone of Earth's life-support system, vital for the survival and well-being of humankind.

J. Michael Fay Explorer, Conservationist As a follow up to his 2,000-mile (3,200 kilometer) walk across the heart of Africa, Fay recently completed eight months in the air. He flew over 60,000 miles (97,000 kilometers) in a specially designed Cessna that captured a high-resolution aerial image every 20 seconds for the sweeping "Megaflyover" project.

John Francis Conservationist Frustrated with his experiences in environmental inaction, Francis decided to effect change by taking a radical personal stand—he stopped using motorized transportation and took a vow of silence that endured for 17 years.

Dereck and Beverly Joubert Photographers, Filmmakers, Naturalists Wild Africa would be in far greater peril if not for the tireless efforts of the Jouberts, who have devoted over 25 years to documenting its majestic wildlife in a race to save countless species—especially lions—from extinction and to help man and beast coexist in greater harmony.

Mattias Klum Photographer A powerhouse in the global conservation movement, Klum recently delivered the opening address at Green Week, an annual event organized by the European Commission to provide a forum for conservation discussion.

Frans Lanting Photographer Best known for his intimate portraits of animals, Lanting is committed to making a difference through his photographs. His recent work documents environmental hotspots.

Kim McKay Conservationist and Author Through her books, large-scale clean-up programs and lectures McKay strives to demonstrate to individuals and corporations that even small steps in going green can make a big difference.

Mark Moffett Ecologist, Photographer E.O. Wilson's protegé and recent Lowell Thomas award-winner is brilliant, quirky and arguably one of the top insect specialists working today.

Nalini Nadkarni Forest Ecologist Thanks to her Big Canopy Database, scientists are finally able to manage and share rain forest data across multiple disciplines—critical to the race to save these essential forests.

Michael "Nick" Nichols Photographer Unadulterated jungle, ferocious tigers, threatened gorillas, and surfing hippos. These are the things that get Nichols up in the morning. His recent book The Last Place on Earth documents his more than two decades of work in Africa.

Paul Nicklen Photographer Growing up in a small Inuit community, Nicklen spent his early years hunting and traveling on land. He quickly developed exceptional field skills and a keen interest in observing wildlife. Now he's one of the top photographers specializing in the Arctic and its inhabitants.

Chad Pregracke Environmentalist Ever wonder if one person can make a significant difference? Chad's story will remove all doubt.

Joel Sartore Photographer Blending a self-deprecating, wry sense of humor with an enthusiasm for his work and a passion for nature, Sartore shares his adventures in the field with National Geographic.

Maria Stenzel Photographer Celebrated for her ability to bring the topic of climate change out of the boardroom and into the living room, Stenzel goes beyond facts and figures to uncover the stories that are emerging as Antarctica, long considered a bellwether, warms and shrinks before us.

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