POTSHOT, by Gerry Boyle, G.P. Putnam’s Sons, hardcover, 304 pages, $24.95.

Jack McMorrow, that modern Don Quixote, the great Knight of the Maine Backwoods, is back in another sterling whodunit.

This is the fourth in a series created by Gerry Boyle, columnist for the Central Maine Morning Sentinel in Waterville, and it is another mystery gem.

McMorrow, Boyle’s one-time New York Times reporter who has opted for the life of a free-lance writer in rural Prosperity, Maine, again gets tangled in a life-threatening situation as he rides to the rescue of mankind. In this case, he attempts to help some rural hippies who are involved with urban drug dealers.

At a county fair, Jack meets Bobby Mullaney, a marijuana-legalization advocate, and his enigmatic sidekick, Coyote. Their fight to legalize growing the weed seems like the kind of feature he might sell to The Boston Globe, so Jack visits Mullaney in his isolated backwoods digs and meets Mullaney’s wife, Melanie, and her angry teen-age son, Stephen. Before he can write his story, Bobby and Coyote disappear. Melanie talks Jack into searching for the duo, supposedly off on a drug buy in Massachusetts.

Jack and his ex-Marine neighbor, Clair, set out to find the two and quickly run into threats and attempts on Jack’s life. They soon learn this is more than just a drug buy gone wrong. The stubborn drive to find out what has happened to Bobby and the mysterious Coyote is sidetracked, too, by a vicious beating administered to Jack’s love, social worker Roxanne Masterson.

The mystery takes a sharp twist as the climax approaches and the solution further threatens Jack.

Boyle’s first-person approach provides neat expressions of McMorrow’s philosophy, somewhat akin to John D. MacDonald’s knight errant, Travis McGee.

For example, McMorrow tells us early on that “I had my good friend Clair and a new chainsaw. I had a hideaway in the hills of Waldo County, Maine. I had built my own house, sort of, and could shoot a rifle straighter than most. I could write the same stories but in small towns instead of big housing projects. I knew the woods and I knew the birds. I read my books, listened to my music, and I bowed to no one, played nobody’s game. On top of all that, I had Roxanne.”

How could we not like Jack or be envious of him?

Later, Jack (Boyle) writes: “I thought that it was all such chaos, everything, all around us, that the only recourse was to try to make a small part of it good, or to chronicle the chaos so at least there was a record to provide a scant semblance of order.”

Besides the philosophy, Boyle also provides a bevy of intriguing characters and warm, friendly descriptions of the Maine scene and its natural beauty.

And it is a real pot-boiler of a murder mystery.

Bill Roach is a free-lance writer with Maine roots who now lives in Florida.