A new book and photography exhibit get up close with Arctic wildlife. Paul Nicklen/National Geographic

As a wildlife photographer, Paul Nicklen doesn't like using his telephoto lens. He prefers lying on his belly in the ice. "Then I know I am getting something good," he says.

That philosophy has led to close encounters with polar bears, elephant seals, walruses and narwhals. The results are captured in his new book Polar Obsession, featuring 150 startling images that document his 15 years as a photojournalist.

Sixty of those images are also on display as part of a free exhibition at the National Geographic Society in Washington, D.C., through Feb. 10.

Nicklen gets close to the animals of the Arctic and Antarctic -- so close that he has nearly lost his life several times. He has been attacked by an 8,000-pound elephant seal, sniffed by a polar bear and charged by grizzlies. The result of this daring proximity is an array of photographs that reveal intimate details of life at the poles.

During one underwater shoot, a leopard seal swam up to Nicklen, who had already been submerged in near-freezing water for an hour, and repeatedly pushed penguins toward his diver's mask, inviting him to join her meal. Nicklen came away with a shot (shown at right) taken almost inside her open jaw -- so close that you can pick out even the bumps on her tongue.

In some of his other photos, narwhals are seen caressing each other with their unicorn-like tusks. A polar bear is caught leaping from ice floe to ice floe, his breath a plume of white smoke.

Nicklen was raised among the Inuit of Baffin Island, in Canada's Arctic. He spent his childhood roaming the icy landscape and learning how to survive it -- perfect training for a career that requires relocating to the world's most unforgiving environments for weeks at a time.

The rush of life on the edge inspires him. The stories behind his adventures accompany the images collected in Polar Obsession, including one hair-raising account of a trip gone wrong, when his broken plane drifted out to sea on an ice floe. We learn how he managed to witness the rarely seen spectacle of polar bears mating. And we know just what he was thinking as that determined leopard seal continued to shove penguins in his face.

Polar Obsession manages to capture the intricate delicacy of these polar wonderlands, teeming with life that could well be snuffed out within the next 20 years. Nicklen provides what few others can: a first-hand account -- in pictures and words -- of how climate change has already ravaged the poles, and how quickly we stand to lose an entire ecology that we have only begun to discover.