John Muir first saw Alaska in 1879, only twelve years after it was purchased from Russia by the United States. Four more times, in 1880, 1881, 1890, and 1899, he was drawn back to this land of rivers and glaciers, sunsets and northern lights, campfires and Arctic stars. Few people have lived so many adventures, yet Muir was not a mere collector of adventure; the hazards he encountered - and many were spine-tingling - came as a result of his intense desire to examine new aspects of the natural world.

In his later life, Muir devoted most of his time to the preservation of the Western forests. He petitioned the U.S. Congress for the National Park Bill that was passed in 1899, establishing both Yosemite and Sequoia National Parks. It was due to the spiritual quality and enthusiasm toward nature which he expressed in his writings that he was able to inspire his readers, including presidents and congressmen, to take action to help preserve large nature areas.