In 1963, Fletcher walked the length of that portion of Grand Canyon contained within the 1963 boundaries of Grand Canyon National Park. Although his route spans only a little more than one-third the length of Grand Canyon, Fletcher was only the second person to complete this section and the first to accomplish the feat "in one go" — as chronicled in his bestselling 1968 memoir "The Man Who Walked Through Time". Fletcher obtained the route information critical for successfully completing his epic trip from the godfather of Grand Canyon hiking, Harvey Butchart, who completed the distance barely ahead of Fletcher the same year — having hiked it one section at a time over 17 years. Through his influential hiker's guide, "The Complete Walker", published the same year, he became a kind of "spiritual godfather" of the wilderness backpacking movement. Through successive editions, this book became the definitive work on the topic and was christened "the Hiker's Bible" by "Field & Stream" magazine.