Robert MacFarlane; the narrator

Robert MacFarlane is a British nature writer who tells the story of Underland largely in first person. He is an avid climber and explorer, climbing glaciers and crawling through the tiny tunnels under Paris in the book. At the beginning of the book, he explains he has spent most of his life obsessed with mountains and has written a great deal about them. MacFarlane's other books of note include Mountains of the Mind, the Old Ways and Landmarks. Although MacFarlane accomplishes technically difficult ice climbs in Underland, he remains humble about his athletic abilities and always enlists guides to help him understand the landscapes in which he travels.

It is clear throughout the book that MacFarlane is a committed environmentalist, although he seems to have little use for most of the rhetoric of the contemporary environmental movement. He explains that he has turned to the...