Stewart Aitchison has been exploring, photographing, teaching, and writing about biodiversity, geology, and the American Southwest for forty years. He frequently travels as a naturalist and photo instructor aboard the National Geographic-Lindblad fleet. Stewart also spent ten years as a field biologist for the Museum of Northern Arizona, a nonprofit institution dedicated to preserving the Colorado Plateau's natural and cultural heritage. His travels and studies have resulted in more than 20 books, including the bestselling Grand Canyon: Window of Time, a photography book focused on the history, geology, and mystery of this natural wonder. His latest book is The Desert Islands of Mexico's Sea of Cortez. Stewart's photos have appeared in National Geographic, Arizona Highways, the Los Angeles Times, Mountain Bike magazine, National Wildlife, Nevada magazine, Outdoor & Travel Photography, Reader's Digest, and Sierra.