For more than a century, National Geographic's writers and photographers have crisscrossed the world, visiting and revisiting the most interesting, dramatic, extraordinary corners of our planet. And month after month enthralled readers and armchair travelers have accompanied them, going places they could never go and meeting people they would never otherwise encounter.

With pictures ranging from familiar American landscapes to exotic foreign scenes, the National Geographic archive is a treasure trove of images and observations -- and this book invites you to explore its wonderful diversity on a journey through time and across the Earth.

Photographs: Then and Now is playful...surprising...downright dazzling. In its provocative pairings of photographs -- one from years past and one from the present -- it offers a wonderful, wide-ranging array of reflections: the world as it was, and as it is today.

Gaze upon New York's Flatiron Building, a marvel of modern architecture circa 1917 -- and see it again in 1989, now dwarfed in scale by Manhattan's towers but still wonderful in its angularity. Here are Australian Aborigines in ancient ceremonial dress and their modern counterpart in jean jacket and cowboy hat. Along with the arresting images that record each far-flung region of the globe, you'll find an essay by a writer who knows the area well and captures its unique character with entertaining eloquence.

Panoramic and perceptive, the kind of book that only National Geographic could create, Photographs: Then and Now is a stunning celebration of our ever-changing, always fascinating world.