Most biographies of Muir draw heavily on his own writings, so the differences among them tend to be minimal. In contrast to Charles Norman's heavily anecdotal life of John Muir (1957), Hildegarde Swift's From the Eagle's Wing was the first to give Muir his full stature as geologist and explorer, and downplay his image as an eccentric hermit. Silverberg's biography focuses on the more contradictory aspects of Muir's personality. A young man with an obvious genius in many fields (geology, botany, invention, business, etc.), Muir was panicked by the prospect of choosing a career (telling himself, ""You will die ere you can do anything else""), and he followed each of his interests in turn with the same nearly self-destructive dedication. In addition, Silverberg stresses Muir's philosophy of nature (""The world, we are told, was made especially for man -- a presumption not supported by all the facts""), which, along with his solitary explorations of mountains and glaciers, should have special appeal for young environmentalists. A more contemporary Muir, but incrementally rather than fundamentally different from his predecessor in Swift.