Isabel Mancinelli was nearing the end of a busy semester at College of the Atlantic in Bar Harbor when she realized her on-campus office had become a maze of paperwork and teaching materials.

The professor of landscape architecture was teaching five different courses, serving on five committees and advising dozens of students when the demands of her hectic schedule caught up with her.

“I would come in from one class or meeting with a pile of stuff, set it down and grab another pile of stuff for another meeting because that was all I had time to do,” she said. “I was winding up with stacks everywhere and not knowing what was where.”

So before another semester could begin, she called in an expert.

With guidance from professional organizer Brenda Cartwright, Mancinelli sorted through the sea of paperwork and set up a labeled system of slots to categorize her teaching materials and committee documents. Cartwright also rearranged the professor’s office to make it more efficient and more welcoming.

“Now when I come in from a class, I can put things in their slot and grab things for another class from another slot,” Mancinelli said. “I’ve learned how much less stressful life can be when you can find things when you need them.”

Mancinelli is one of many people across the nation who have enlisted the expertise of a professional organizer, someone skilled in the art of helping people sort through their messes and instill order in their lives.

The National Association of Professional Organizers reports it has more than 3,350 members working in the United States and in eight other countries.

In Maine, Cartwright has been helping people get organized for more than 18 years. In that time, she has assisted a variety of clients, from business owners to stay-at-home moms, who have felt overwhelmed by their cluttered surroundings and their unsystematic ways.

“People hire me because they want to put the pencils in the pencil cup. They want to be organized,” said Cartwright, who operates The Organizer Inc. in Ellsworth. “But what I find nine times out of 10 is that they’ve got other issues and the organization is what is tripping them up. Often it is not about putting their stuff in order. It’s about something else.”

For some, the source of their clutter is a busy lifestyle. Those are the clients who need help with time management. For others, the culprit is an accumulation of items they, for whatever reason, are unable to throw away.

“We are totally overwhelmed with stuff,” she said. “We live in a consumer society where more is better. For some people, they can handle it. But for others, they can’t throw the old things out.”

Mike Nelson, author of three books, including “Stop Clutter from Wrecking Your Family,” says clutter, which he defines as any items that are kept even though they are no longer needed or used, becomes a problem when it begins to limit a person’s life.

“Clutterers tend to be isolationists,” he said during a telephone interview from his home in McAllen, Texas. “They won’t let anybody in their house. If you have a family, it could cause friction between the spouses. If you are in business, clutter costs money. The clutter occupies your mind.”

Clutterers, he said, are unable to make decisions about what to throw away, often because of fear or insecurity. They are afraid they will either get rid of something they need or something that has sentimental value.

“We feel like if we throw out something that somebody gave us, then we are throwing out the person, the memory,” he said. “We don’t trust our memories.”

Nelson, himself a clutterer in recovery, lost all his belongings, including irreplaceable photographs and slides, last year in a house fire. The traumatic event forced him to consider what possessions he needs and what he can live without.

“I just don’t have a lot of stuff like I used to,” he said. “You are not your stuff. Stuff is stuff and you are you, and you are more important.”

Sandy Imondi, a professional organizer from Brewer, said she too has seen clients struggle with their emotional attachments to objects. The key to helping them sort through their belongings, she said, is asking the right questions and taking the process one step at a time.

“They need to be ready to let go,” she said. “Organizing isn’t about just throwing away things. It is helping someone get through the emotional process of [asking themselves], ‘Do I need this?'”

Imondi, whose business is called Organized Solutions, has helped people get control over their offices, garages, basements, even the junk drawers in their homes. She has seen houses where residents have stacked papers and others items from the floor to the ceiling, leaving only pathways to get from room to room.

Going through that much stuff is emotionally and physically draining.

“The clients are more exhausted at the end of the day than I am,” she said. “It is so personal. You are in people’s things, their finances. You’re touching the baby clothes that have been tucked in their drawers. But it is also so emotionally satisfying to see the client grow as well.”

Cartwright sees another reason why people, particularly New Englanders who grew up during the Depression era, are reluctant to toss things out.

“It’s Yankee ingenuity,” she said. Instead of throwing away an old toaster, for example, they put it in the garage in case they can reuse it for parts someday. “They’ve bought it and they don’t want to get rid of it. It’s being frugal and we are proud of that.”

In recent years, television programs such as “Clean Sweep” on The Learning Channel have popularized the notion of calling a professional organizer. But Nelson, who has traveled the country giving seminars on letting go of clutter, is leery about the message that those quick-fix shows send to viewers.

It might make for good TV to straighten out a messy homeowner overnight, but getting to the root of the problem takes a bit longer and requires real lifestyle changes.

“It’s about slow growth,” he said.

In 2000, Nelson founded a nonprofit organization called the Clutterless Recovery Group to help people understand the psychological aspects of their habits and to cope with the shame associated with being a clutterer.

At a handful of support groups around the country, members meet weekly to talk about their struggles and to make small but positive steps toward establishing order in their lives.

“For most of us, it is a lifelong battle. For me it is,” he said. “People have called us slobs, messy people … lazy. That’s got nothing to do with it, but that is how we are programmed to think about ourselves.”

Professional organizers are in high demand and their services aren’t cheap. Cartwright charges $50 an hour, and an Internet search for organizers in other parts of the country revealed some charge a lot more than that.

But many people, such as Mancinelli, are finding the expense is worth the result.

“The time it has saved me, it has been invaluable,” she said.