Meandering and insightful, personal and historical, metaphorical and biological, Solnit's Field Guide is not a guide at all but a beautifully written collection of essays finding the contours of the unknown: its dangers, its wonder, the blind hubris with which we, humans, try to devour it.
She has that magical capacity that some writers have to color even the air in each scene. We know, though she doesn't say it, when tragedy is imminent or when sex has happened.
Her data points are wide-ranging: Renaissance painters, gold miners, the underdeveloped Midge from Hitchcock's Vertigo, Spanish conquistadors, and she moves with a litheness from one idea to the next, each connection rewarding and surprising.
There is no whimsy here. She looks to the terra incognita as an experienced sailor might look to the immense sea: with deep personal knowledge of its beauty and equally its power to destroy.