For more than half a century, mountaineer David Roberts has ventured into the unknown, climbing peaks, running untested waterways and hiking into canyons that haven't been visited by humans for hundreds of years. In Limits of the Known, Roberts wistfully recounts many of his adventures, triumphs and a few unsuccessful attempts, while coming to grips with the fact that he is dying of throat and lung cancer.
He skillfully blends his own narratives with those of the explorers and adventurers who have come before him, and of those who are undertaking expeditions in areas where Roberts is not a master. Readers learn of the trials polar explorers endured in the late 1800s and early 1900s, when being the first to reach the poles captured the imagination and spurred those who were willing to push themselves to impossible limits. Once the poles were obtained, climbing the highest summits in the world became the next target, which Roberts readily admits became his own passion and obsession.
Always seeking the next adrenaline rush, Roberts also joined several whitewater rafting expeditions where he plunged down unknown rivers, despite his inability to swim. This in turn leads to cave explorations. These tales are juxtaposed against Roberts's slow acknowledgement that he will no longer be at the forefront of any of these new explorations, that death is the last great unknown. Limits of the Known can be considered Roberts's swan song, a beautiful treatise on the extremes humans will go to in order better to understand ourselves and the world we live in for such a brief time. --Lee E. Cart, freelance writer and book reviewer