BERND HEINRICH’S Summer World is the completion of an eclectic exploration of the seasons that he began in Winter World. The book is based on a set of observations made in rural Vermont and Maine, but much of what he describes has universal resonance. This is good old-fashioned nature writing of the out-my-backdoor variety and the how-this-here-relates-to-the-Universe philosophy. Heinrich is a master of this craft.

The author started his working life as a professor of entomology at the University of California, Berkeley, spent time as a Guggenheim and Harvard fellow, and is now a professor emeritus in the biology department of the University of Vermont. He’s written more than a dozen natural history books, so by now he is a trusted friend. We may expect certain things from him — professorial exactitude, risky playfulness — and they’re all here for us to enjoy.

Here the progress of a summer season provides a handy footpath for Heinrich to wander, and for us to follow. There are digressions along the way to places as distant as the deserts of the Namib and Negev, to the evolutionary biology of human clothes and the design of dinosaur nesting colonies.

As a writer, Heinrich is relaxed about language and obsessed with his subjects.

At first the writing can seem deceptively dry — almost tedious: “It is snowing hard (again!),” he says in frustration, as if he were our brother nattering on the phone. But soon enough we’re in there with him and just as fed up by the weather and just as fascinated by the novel gyrations at his bird feeder. Suddenly he’s upending trash cans over his crocuses, trying to figure out why and how flowers open . . . and shut . . . and open again. Later he fools around with hornets’ nests — with predictable (and unpredictable) results, and spends hours sitting on a homemade platform twenty feet up in the woods watching the action at sapsucker “licks.” The antics of his backyard research took me back to childhood afternoons spent putting pupae in jars so I could watch butterflies hatch, to glorious hours spent on my belly watching frogs, uh . . . do it. Heinrich spends more time on his belly in this occupation than I ever did.

This is the doing of science. This is science as fun. As a pursuit. Heinrich takes meticulous notes and makes sketches of everything that catches his eye, and most things do. The book is filled with his illustrations. He tackles bigger issues — energy use, climate change — between lapidary examinations of moss. It’s hard to say which is more urgent, or that the two are unrelated. He is showing us creatures we have never seen, strategies we have never considered, linkages we could never imagine.