Environmental Protection

In Beaver World

My First Summer in the Sierra (With Original Drawings & Photographs)

The Rocky Mountain Wonderland

A Pictorial Guide to Mesa Verde National Park

The Arctic Prairies : a Canoe-Journey of 2,000 Miles in Search of the Caribou

The Wilderness Castaways

Jane Goodall: 50 Years at Gombe

A Rough Ride to the Future

Thornton Burgess: Collected Works

Views of Nature – Contemplations on the Sublime Phenomena of Creation with Scientific Illustrations

In the Catskills: Selections from the Writings of John Burroughs

Good hunting; in pursuit of big game in the West

Morag the Seal

How to Camp Out

Sketches in Duneland

The Future of Conservation in America

The Chemical Age

Adventure Travel Unleashed

The Wisdom of Albert Schweitzer

The New 50 Simple Things Kids Can Do to Save the Earth