There is no evidence yet that a cougar is roaming through the northwest suburbs, he said, emphasizing that would require confirmation by a wildlife expert or DNA testing of the animal's scat or hair.

Longtime state wildlife division biologist Jim Cardoza agreed with Miller's assessment.

"We get dozens of sighting reports every year, but there is little evidence" to back them up, Cardoza said. So the notion that there is a cougar population in Massachusetts doesn't carry much weight in his mind, he said, unless it is a captured cougar let loose by its owner, which happens from time to time.

The only confirmed evidence, through DNA testing, of a cougar in the wild in this state was in 1997, on the western edge of the Quabbin Reservoir, Cardoza and Miller noted.

In addition, there has been a confirmed report in Vermont and another in Maine since 1990, Miller said. During that time, there have been a total of 49 confirmations, 88 "probables," and "seven confirmations waiting to be verified," in an area stretching from Quebec to northern Florida and west to the prairie states, he said. "Cougars appear to be coming back - particularly in the prairie states - because there's more plentiful prey again, such as deer."

Miller, who spent much of his youth in Littleton, N.H., said he has always "been interested in wildlife, especially the mysterious big cats, of which the cougar was the only one in the East."

While studying up on cougars, he also forged a successful career in high technology, starting two companies as a data communications specialist. Later, he fine-tuned his tennis game and attained senior rankings regionally and nationally.

His wife, Dorcas, 62, a residential real estate agent in Concord, is also a ranked senior tennis player in New England and nationally.

Concord residents since 1969, they have lived the last seven years in a house overlooking White Pond, once described by Henry David Thoreau as "the gem of the woods." They have a son, Gary, 35, of Newton, and a married daughter, Rachel Amato, 32, of Westford, and one grandson.

"Ken is a telecommunications visionary, someone who could spot a customer's problem right away," recalled Jim Rothrock of Westbrook, Maine, who met Miller in 1972 when both worked for Codex Corp. in Newton.

Later, Rothrock was a board member of Concord Data Systems, which Miller founded in 1981.

"I remember Ken telling Western Union, a Codex customer, that he could make a modem for them that would work. They gave him a shot at it, and the product did work. Others would have taken the easy route, letting the customer come up with the ideas," Rothrock said.

Early on, Miller said he wanted "to do something scientific" and to be his own boss, following the example of his late father, who had operated a New Hampshire resort.

After receiving bachelor's and master's degrees in electrical engineering from Rensselaer Polytechnic Institute and the University of Pennsylvania, respectively, he worked as an engineer for Raytheon, Honeywell, and several small companies. He subsequently joined Codex and formed Concord Data Systems, a part of which was spun off into Concord Communications, now a Marlborough-based business software firm.

In 1992, he founded Prism Networks of Waltham. Three years later, Prism became StarBurst Software, which was sold to the then-Adero, also of Waltham, in 2000. He is now a part-time consultant to Bandwiz, an Israeli start-up software firm with offices in Framingham. He is also on the company's board.

Semiretirement now means that Miller has more time for a recreational addiction - tennis.

Last year, in the 60-and-over category, he was ranked fifth in doubles and 11th in singles in New England, 69th in singles and 11th in doubles nationally. He is also commissioner of the spring Suburban Tennis League, made up of men's doubles teams in Greater Boston. "Since being semiretired, I've been able to work a lot on improving my game, with the help of Rocky Jarvis, the Brandeis tennis coach," said Miller, who's also a hiking aficionado.

He and his wife have traveled as far away as New Zealand for hiking expeditions.

Rothrock, his former colleague, said of Miller's tennis: "When he decides to do something, he does it intensely, yet with patience."

Miller's patience also paid off in crafting the cougar website, said Mark Dowling of Newtown, Conn., who, with Jim Close of Mechanicsville, N.Y., and Bob Wilson of Garden City, Kan., worked on the project.

But what really characterizes Miller is "his interest in always trying new things that are fun," said his wife.

But the mysterious cougar is always on Miller's mind. "We're talking about a potentially great success story," he said of the animal's reemergence.