My First Summer in the Sierra describes two years period of Muir's life during which he lived in a cabin in Californian mountains. When he came to California and finally settled in San Francisco, John Muir immediately left for a visit to Yosemite, a place he had only read about. Seeing it for the first time, Muir noted that "He was overwhelmed by the landscape, scrambling down steep cliff faces to get a closer look at the waterfalls, whooping and howling at the vistas, jumping tirelessly from flower to flower." He climbed a number of mountains, including Cathedral Peak and Mount Dana, and hiked the old Indian trail down Bloody Canyon to Mono Lake.

John Muir (1838-1914) also known as "John of the Mountains" and the "Father of the National Parks", was an influential Scottish-American naturalist, author, environmental philosopher, glaciologist, and early advocate for the preservation of wilderness in the United States of America. His letters, essays, and books describing his adventures in nature, especially in the Sierra Nevada, have been read by millions. His activism has helped to preserve the Yosemite Valley, Sequoia National Park and many other wilderness areas.