At the time of his death Muir had in preparation a second volume of his auto biography. Though very incomplete, it was found so important that it seemed best to in corporate it in the present work, whose form of presentation and selection of materials had to be accommodated somewhat to make this possible. It is chie?y in the letters, however, that the reader will find revealed the charm of Muir's personality and the spontaneity of his nature enthusiasms.