In comparing Eiseley with Thoreau, he discusses clear similarities in their life and philosophies. He notes that Eiseley was, like Thoreau, a 'spiritual wanderer through the deserts of the modern world.' However, notes Wentz, "Thoreau had left the seclusion of Walden Pond in order to pace the fields of history, sorting out the artifacts that people had dropped along the way." But "it was those 'fossil thoughts' and 'mindprints' that Eiseley himself explored in his wanderings. These explorations gave depth, a tragic dimension and catharsis to what he called the 'one great drama that concerns us most, the supreme mystery, man.'"