The New Hampshire sized Klamath/Siskiyou bioregion in northwest California and southwest Oregon rivals the Sierra Nevada and Cascades as a locus of biodiversity and wilderness values-- and it has qualities less typical of those areas-- major salmon rivers and vital indigenous communities.
An even worse effect of this neglect was that it remained unprotected from logging, mining, and dams, which caused considerable damage, particularly after WW II, when the U.S. Forest Service characterized it as "ordinary mountain country" and clear cut much of it.
Since the book's publication, the International Union for the Conservation of Nature and other organizations have acknowledged the Klamath/Siskiyou region's global significance, although attempts to place more of it in the national park system have met stubborn political resistance.
While praising the book's natural history content, it accused Wallace of playing "fast and loose" with concepts like evolution and mythology "in a grab for cosmic significance" and of sinking "quickly and deeply into a mire of pretension" with "attempts to alchemize science into poetry."
The Atlantic Monthly (February, 1983) wrote: "Mr. Wallace, rambling observantly about the area, has found functioning examples [of evolution] from all the earth's history, which he describes with authority, charm, and a discreet touch of imagination."
His fifth book, The Turquoise Dragon (Sierra Club, 1985) is an "eco-thriller" set in the region's Trinity Alps and Kalmiopsis wilderness areas, which explores issues like biodiversity and resource exploitation by inventing an endangered species as the focus of a murder mystery.
One of his latest books, Articulate Earth (Backcountry Press, 2014) collects a number of articles published about the region during the past four decades in venues like Wilderness magazine, Backpacker, Mother Jones, Greenpeace, and the Sierra Club calendar.