History was not David Allen's profession, but in recent years it has been his passion.

Allen spent years in social work, specializing in psychotherapy. During that time, he had to take case histories of his clients. But now he pursues history itself.

"I call it a passion, my wife calls it an obsession," said Allen, who has been hosting seasonal historical walks in the city for several years.

"Basically, I have always had a curious mind, from childhood.

"I like history because I am dealing with dead people that can't argue with you," he joked, saying he researches for fun. "I don't have the money to publish the information that I gather, so I decided to share it with others during the walks."

Allen began researching city history when he moved to Butler in 2000.

"I moved here from Armstrong County and found myself with time on my hands while I did physical rehabilitation on a mountain bike for a year," Allen explained.

"The city was tearing down buildings at that time and my wife and I were upset at the history that was being destroyed," he said.

Allen then launched an intense research campaign, poring over microfilm, deeds and archival maps.

He set up camp at the Butler Public Library and Butler County Historical Society and discovered some of Butler's colorful past.

Allen spends about 20 hours per week doing the historical research at various county locations. Each guided historical walk has taken about six months to prepare.

His topics have included industry along the Connoquenessing Creek, downtown Butler in the 1820s, and the history of bottling in the city. This year's guided historical walk will focus on industry in another part of the city.

Ginger Dlutowski, along with some of her friends in the local chapter of the Red Hat Society, attended the walk last year.

"We met up with David in Butler and had a delightful walk as he told us information about Butler - things we'd never known," she said. "He has so many interesting tidbits that make the past come to life.

"It's not like a history lesson because he makes it personal and ties his facts together with the interesting trivia," she said. "He has such a wealth of knowledge. It was so enjoyable that we are looking forward to the next one and making plans to take the walk."

Rebecca Crum-Reinsel, executive director of the historical society, appreciates Allen for his ability to get the facts and his desire to share them.

"Dave is an avid history researcher. His passion for the subject is exhibited in his continued enthusiasm and willingness to share it with the community of Butler," she said. "The historical society is pleased to have him as a volunteer and appreciates his programs on the organization's behalf."

While Allen does not charge for the walks, he does accept donations for the historical society.

One thing Allen would like to convey on this year's trip back in time is the accomplishments of Butler's visionaries.

"My research has led me to discover interesting and productive people," he said. "I'd like to show that life can be successful. When people have vision and energy and tenacity they can accomplish great things."

Allen said he learned about a fellow named Springdale, and about how William S. Boyd of Butler was in his 60s when he was most productive in shaping the role Butler would have in the Industrial Revolution.

This year, the subject of his history walk, 100 Years of Industry on the South Side, was chosen because of the dramatic changes that are occurring in that region.

"We will be talking about the earliest foundry, the second earliest grist mill and other industries related to glass making, as well as a commercial bakery that was located here," said Allen.

"We have three Butler bridges that are all undergoing construction or change.

"Monroe, South Main and Wayne street are all in the process of change," said Allen of the tour, which will explore industry from 1840 to 1940 in that part of the city.

Participants can meet up with Allen every Wednesday evening at 6 p.m. during the summer months at the corner of East Cunningham and East Monroe streets.

The 2½-mile walk will last about two hours and explores the corridor between East Jefferson and South Main streets.

"I'm orthopedically challenged, so I don't walk fast," he said of the tour's accessibility to all ages.

Allen is also in the planning stages for next year's project, which will feature Alameda Park.