If Miles Davis suddenly walked into a small cocktail party, what could a young trumpet player possibly say to him? What could I, a greenhorn writer, say to Peter Matthiessen? It was 1998. I was in my early forties, and had just published my first book. Peter was past 70; the first of his novels, Race Rock, was published in 1954. Anything I could think of saying seemed lame. Then Peter took two steps toward me and ended my dilemma: “So, Carl, when are we going fishing?” Peter had fishing friends and birding friends and writing friends (and political enemies). His strong opinions often incited debates. We disagreed a bit about fishing policies—he’d fished commercially, and I’d advocated sharp catch limits for men he’d worked with. But I never found him unreasonable, or grudging in conceding a point. Anyway, on the broader unraveling of both civilization and the natural world, we saw eye to eye, both in anger and in hope. Our biggest disagreement was on the value of his...