Apparently, all 3 parts of this book were articles in the New Yorker. I've alwasys enjoyed his writings on science, this one includes a look at the San Gabriel mountains near where I live, which is good, since I still haven't forgiven him for short-shrifting Southern California in "Assembling California." I get the impression he didn't find the San Gabriel mountains very interesting.
Recommend this author highly. He is one of the best non-fiction writers of all time and this is one of his best.
McPhee is an excellent communicator and naturalist...this is another accomplishment of his.
Three New Yorker-length articles (that's where they were first published) on the Atchafalaya River in Louisiana, Iceland's Heimay volcano, and the San Gabriel Mountains. His books are crying out for maps, but for some reason, he doesn't add any photos or maps (some drawings of Icelandic houses, which seem very tangential to the main story), fortunately, we live in the age of Googleearth, so I was able to find most (but not all) places he mentioned.