"JOHN MUIR, Earth-planet, Universe."—These words are written on the inside cover of the notebook from which the contents of this volume have been taken. They reflect the mood in which the late author and explorer undertook his thousand-mile walk to the Gulf of Mexico. No less does this refreshingly cosmopolitan address, which might have startled any finder of the book, reveal the temper and the comprehensiveness of Mr. Muir's mind. He never was and never could be a parochial student of nature. In September 1867, Muir undertook a walk of about 1,000 miles (1,600 km) from Kentucky to Florida, which he recounted in his book A Thousand-Mile Walk to the Gulf. He had no specific route chosen, except to go by the "wildest, leafiest, and least trodden way I could find."