So why is he interested in this telescoping rod? Why the 18-wheeled trucks of the title essay in his earlier book “Uncommon Carriers”? Why did he dedicate so many words to oranges in the brilliantly titled “Oranges”? “Compulsions are easy to come by and hard to explain,” McPhee admits in this new collection. Over the years, with generosity, he’s shared them. “I have never spent time with anyone who was more aware of the natural world.” This is how McPhee described a mineral engineer in one of his finest books, “Encounters With the Archdruid,” adding, “He seemed to find in the land and landscape … an expression of almost everything he had come to believe about that world.” With time, the description now shines back on its author.

“The Patch” is billed as a “covert memoir,” but McPhee has smuggled excerpts from his life into most of his books. “When you are deciding what to leave out, begin with the author,” he warned students in his recent writing memoir, “Draft No. 4.” “If you see yourself prancing around between subject and reader, get lost.” Never a known prancer, McPhee has instead drifted gracefully alongside his interviewees, in motion and in communion, in canoes and the cabs of trucks, listening with an almost obsolete respect to both sides of our various divides: to the mineral engineer and the environmentalist. “The Patch” is just another chapter in an ongoing memoir of generous curiosity.

It’s McPhee’s way to prod landscape and people until an avalanche of the verifiable tumbles into his notebooks. He is never one to simply walk through a meadow when the path passes “heather, lupine, horsemint, daisies and wild licorice.” The color and fragrance of his writing could easily turn sickly if they didn’t yield up the world with such precision, if they weren’t deployed in the service of greater meaning.

Case in point: In the first and best essay in this collection, he vividly introduces the latest thing-you-didn’t-know-you-cared-about: the chain pickerel, a fish with a “culinary quality … in inverse proportion to its size.” As expected, McPhee describes an explosive “slime dart” that treads water “in much the way that a hummingbird treads air.” But he ensures that the essay is as much about the legacy of his dying father. The image of a fish “as voracious as insurance companies, as greedy as banks” lingers like a splash, but the lasting impression is that of a patient lying in a hospital bed while his son tells him what he caught that morning with the old man’s bamboo fishing pole.

About the only essay in this collection that McPhee can’t elevate is an account of an N.C.A.A. lacrosse game pitting the University of Denver against Syracuse. McPhee is, thankfully, human in the face of a few daunting subjects. Even with his faultless sentences, research and structure, the subject remains, with earthbound obstinacy, a game of lacrosse.