In PaperbackWalden's Shore:Henry David Thoreau and Nineteenth-Century Science by Robert M. ThorsonHarvard University Press, 2015There's a fine line geology professor Robert Thorson walks in his utterly fascinating book Walden's Shore, now out in a somber paperback (it has, contain yourself now, the picture of a rock on the cover), and he actually quotes the legendary E. O. Wilson on the tectonic plates sitting on either side of that fine line: “The love of complexity without reductionism makes art,” Wilson writes in Consilience, “The love of complexity with reductionism makes science.”The gray area between those two extremes has always been the home of pedants and bores, and the most amazing thing about Walden's Shore is how often Thorson travels in that gray area, how often he consorts with those bores and pedants and consults their works, without actually himself becoming either a bore or a pedant. Instead, he delivers great blocks of the geophysical science about the geography of Walden Pond without ever letting his prose become as boring as his book's cover would lead you to expect. Take humble granite, for instance, the humble granite that carpets the whole Nashoba Valley where Walden is located. When Thorson explains it, you get a clear glimpse of how good his classes must be:

Normally we think of granite – and its close kin, granite gneiss – as a strong rock. And it certainly is, mechanically speaking. But chemically, it can be fairly weak, especially when the crystals are coarse-grained and when it is exposed to a warm humid climate of the sort that characterized Nashoba for nearly all of its geological history. Between resistant grains of quartz and feldspar are books of mica: a light-colored one called muscovite, also known as white mica, and a dark one called biotite, also known as black mica. Both quickly disintegrate into clay, the black one also contributing to the familiar yellow stain of soil. Also present are peg-shaped iron-rich minerals called amphiboles, which dissolved nearly as fast. When these weak mineral links dissolve and heave apart, the resulting mass readily disintegrates into jagged sands of the sort you can find in practically every New England brook.

Thorson is steeped in the actual content of Thoreau's 1854 classic, and he provides as many nature-quotes as any Walden fan could want, but re-reading his book in paperback emphasizes even more sharply that Thorson's own nature-insights are the main attractions here. He can take his narrative into the oldest history of the planet, to Earth billions of years ago, and make it every bit as intriguing and evocative as Thoreau could make an acorn in his path:

A time when its oldest microbes were evolving on some boiling volcanic vent, probably in the pitch dark below a global abyssal sea. Somewhere on the gradient between geothermal scald and oceanic cold was the ideal Goldilocks temperature of “just right.” The microbes that found it survived best, thereby launching the evolution of human sensation. This touch of heat almost certainly preceded other aspects of touch such as pressure and texture.

In studying Thoreau's own debts to the science-writers of his time, Thorson opens up Walden from its sometimes insular grandeur and grounds (so to speak) its mytho-poetics in the physical properties of the place Thoreau made famous. It's a pleasure to welcome the book back in paperback, whether it looks like an Amish hymnal or not.