Mark Twain once said, “If dogs could talk, no one would own one.” Tom Shelby, a lifelong dog trainer with a specialty in search and rescue dogs, chuckles at Mr. Twain’s quote. Mr. Shelby understands canine thinking better than anyone, and still loves them.

“If we could even grasp a dog’s sense of smell, we would realize how dramatically different they are from us,” Mr. Shelby explained. With the exception of the crushed-faced breeds such as pugs, most dogs are able to sniff a cadaver located 90 feet under water.

Over the past few summers, many have spotted Mr. Shelby on the hillside just west of Sunset Lake, walking his black Doberman, Michael (who died at the age of 9 last April), and his Min-Pin, MacDuff, who could fit into a porcelain gravy boat. The first thing one noticed over the years was how well-trained the two dogs were. A squirrel might dart past, or a tasty looking carton of half-eaten fries beckon from the ground.

“Leave it,” Mr. Shelby would say, and the dogs would spring back to their owner’s side, aligned like a pair of soldiers beside his left leg.

It’s a pleasure to spend time with Mr. Shelby because he glows with the happiness of having spent a lifetime doing what he adores: Being with dogs and training them to the best of his ability, which just happens to be at a level of brilliance. Although he hasn’t reached the fame of Cesar Millan, he too has published a book, Michelle and Me, about his adventures with the first of his rescue dogs, the late Michael having been his second. He’s now at work on a new book about dog training called Dog Trainer Diaries.

Formerly a New Yorker, Mr. Shelby and his wife, Jaye, a retired professor of speech pathology from St. Thomas Aquinas College, bought a Camp Ground cottage in 2001. They moved here full-time in 2010.

“I’m not retired,” says Mr. Shelby, “I’m rewired.”

Accustomed to a former caseload of up to 900 dogs a year, Mr. Shelby still takes on new clients. His client base in New York included Erica Jong and the Swiss ambassador, who ended up giving him MacDuff. Mr. Shelby understands that the Island year-round population is not as affluent as his former clients in New York and has lowered his fees accordingly.

The trainer first became interested in animals when he roomed in a house in Kew Gardens, N.Y. that also housed a number of cats, dogs, hamsters, and even snakes. Instead of being appalled, he loved his furry and scaly roommates. At the time he was also a motorcycle enthusiast, riding and repairing them, and he decided to open a business called Cycle Doctors. The business thrived, but he was operating without a license and before long it had to be dissolved.

One day while reading the paper at his mother’s apartment, he saw an advertisement for a dog trainer, experience required. He set up an interview with the training firm, then holed up for the weekend with two books on canine deportment: Good Dog, Bad Dog by Siegal and Margolis, and Guard Dog Training by William Koehler, both still in print.

At the interview he was given a cocker spaniel to train. Mr. Shelby showed a knack for handling the dog, and was hired immediately. Six months later he was also asked to work for Bide A Wee and the Humane Society in Manhattan. When the company that offered him his first job folded, Mr. Shelby followed through on another advertisement to work with a man in Brooklyn who handled guard dogs.

Mr. Shelby’s audition involved petting a slavering, barking, spitting German shepherd tied to a long cord. For 15 minutes Mr. Shelby sat just beyond reach of the dog until it calmed down. Then Mr. Shelby commanded the dog to “Sit” and the dog complied. Mr. Shelby approached the dog and patted its head. Thinking his work was done, he was startled by the follow-up order from the guard dog owner.

“Now you’ve got to un-do what you’ve done [causing the dog to feel friendly towards a stranger],” the owner, Eddie Rivera, said. These were guard dogs in training, after all. Mr. Rivera told him to smack the dog with his jacket.

Mr. Shelby did as he was told, firing up the dog into attack mode again, before scooting safely out of the way. He won the job.

Mr. Shelby still regards Eddie Rivera as the finest handler of aggressive dogs he has known. One night when he and Mr. Rivera strolled past a junkyard, two depraved dogs hurled themselves against the chain link fence. “These dogs are all bluster,” Mr. Rivera said. He vaulted over the fence and shouted the dogs into a submissive huddle. For an encore he removed their collars and left them with a note regarding his services pinned to the closed office door.

Mr. Shelby eventually began to work in the field of search and rescue. He had moved with his wife and three children to Rockland County. One cold night he received a call from the police to help with a search; a 74-year-old man had wandered off a path during a hike. Mr. Shelby introduced his dog, Michelle, to the man’s smell by placing her in the driver’s seat of the man’s car. She quickly found him.

“It was a live find,” said Mr. Shelby, using search and rescue jargon.

Impressed, the chief of police asked the trainer to join his K-9 team. “That’s how I became a cop,” Mr. Shelby said.

His work for the police often involved being summoned at three o’clock in the morning to head out into the dark mountains with Michelle. It was always an enormous relief to recover a person still alive and, conversely, a tragedy when the victim was dead. Often times Mr. Shelby knew from the start that the search involved a cadaver, but it was still essential to recover the body.

The high drama of search and rescue is largely over for Mr. Shelby, yet he remains interested in every aspect of canine behavior. But in social settings Mr. Shelby sometimes resists telling people his profession. Everyone wants some free advice. Nonetheless, he does seem happy to share his knowledge when you run into him along the banks of Sunset Lake.

To find out more about Mr. Shelby visit his Web site at dogsrshelby.com. And if a weekend houseguest has wandered into the State Forest, well, we’ll have to wait for Mr. Shelby to find a good replacement for Michelle before he resumes search and rescue. Hopefully that will happen soon.

After all, tiny MacDuff needs a buddy.