This book is really three books in one. It is a guidebook for a walking/cycling route across California that follows John Muir's footsteps from San Francisco to Yosemite via the Pacheco Pass. It is an adventure book, telling the story of Peter and Donna Thomas' 2006 ramble across California to discover that route. And finally it is a history book, presenting in its entirety and for the first time, the complete story of John Muir's first trip to Yosemite. That trip was taken in 1868, the year before Muir's "First Summer in the Sierra," and it has never been published before, existing in obscurity, in Muir's various writings, until it was reconstructed by Peter and Donna in preparation for their walk to Yosemite in his footsteps.