On Wednesday, June 21, hundreds of mourners filled the grassy quadrangle at West End Place in downtown Boston to celebrate the life of Robert H. Kuehn, one of this country's foremost developers of affordable housing and a leading light in the rehabilitation of our nation's historic buildings. It was a fitting location because it embodied the spirit of Bob's lifelong crusade to discover and breathe life back into places that had fallen into desuetude due to neglect and a lack of historical sensitivity.

In the 1950s, Boston's West End was a vibrant working class community celebrated in the famous Herbert Gans book The Urban Villagers. But with the advent of urban renewal, the working class neighborhood of triple deckers was torn down and replaced by luxury apartments. The destruction of the West End and the psychological impact on its dispossessed urban villagers became the lore of sociologists and urban planners for the next quarter century. In 1994, Bob learned that a single parcel of land might be available in the West End for mixed income housing. He was fascinated by the prospect of bringing life back into the old neighborhood. He thoroughly researched its history and went so far as to contact families who had formerly lived in the West End. Bob was so pleased with the success of the project that he chose to live in West End Place.

Bob Kuehn was born Oct. 27, 1942, in Minneapolis, Minn. He graduated from Minneapolis North High School in 1960. He attended Yale University, graduated in 1964 and moved a few blocks down York Street to attend Yale's school of architecture. Bob enjoyed designing buildings but soon realized that what ultimately gets built has less to do with the architect than with the whims of the developer. Combining this insight with a growing concern that suitable places to live be provided for all Americans, he decided to specialize in affordable housing. In 1968, he earned a double degree - a master's in urban studies and another in architecture from Yale. In 1969 he was a Fulbright Scholar at the University of London.

As a thesis project at Yale, he developed a computer program that analyzed the available subsidies for building affordable housing, a tool that became the basis for a national industry of syndication of investment in real estate projects. He designed this program at a time when personal computers were a distant dream, learning the early clunky languages that were used to converse with huge mainframe machines attended by acolytes in air conditioned buildings. To learn the finesse of development, Bob spent his early years as a consultant to developers - First Realty of Boston being the most prominent - learning the trade firsthand, before branching out on his own.

Old unused buildings seemed to call to Bob. It was as if he could feel the tremor of the machinery and the thump of workers' footsteps and he wanted to - literally - bring those sounds back. In 1976, he founded Keen Development Corporation and began to specialize in the rehabilitation of historic buildings and their conversion to mixed-income housing. He was especially adept at finding innovative sources of funding and inventing new ways to work with community organizations to achieve mutually beneficial goals.

One project that he spoke of almost constantly and always fondly was the Baker Chocolate Factory in Dorchester Lower Mills, a gem from Boston's industrial past. On the banks of the Neponset River, the factory made chocolates in the 1800s and continued until the company relocated in 1964 when the buildings fell into disrepair for almost two decades. Bob saw the fading beauty of their ornate façades and towers and, in 1982, began their renovation. Today, Baker Chocolate Factory contains 133 apartments at moderate rents and has contributed significantly to the revitalization of the surrounding neighborhood.

Bob was convinced that the life of any great town or city depended on the vitality that artists brought to their community, and he worked hard to create places for them to live and work. In Cambridge, for example, he helped a community of artists purchase and renovate Fenway Studios. The artists formed a group called Artists for the Preservation of the Fenway Studios and when they could not find local banks willing to provide a mortgage, he loaned them money to help keep the effort going and finally secured a mortgage for them from a bank in Washington. The artists formed a not-for-profit cooperative, the building was successfully renovated, eventually placed on the National Register of Historic Places and has since become a business model for future artists' cooperatives. Bob followed up with other successful Artists Live and Work projects (places where artists both have their studios and reside), among them Midway studios and 300 Summer street in Boston's Fort Point neighborhood, Smith Lofts in Providence, R.I., and Kennedy Biscuit Lofts in Cambridge (the birthplace of the famous Fig Newton).

Among Bob's most daunting projects was the renovation of one of Boston's most infamous housing projects, Columbia Point. In 1985, Columbia Point had become a crime-ridden no-man's-land with only about 350 of the 1,500 apartments still occupied. Bob and two other partners worked with a task force of local residents who believed in the vision of converting the blighted development into mixed income housing. Rehabilitation on this scale had never been tried before in Boston. The grid of buildings was cleverly redesigned so that views were opened to Boston harbor, and what was once a series of bland buildings was converted to a neighborhood of midrise apartments and two to three-story townhouses. Now called Harbor Point, the successful mixed income community comprises 1,283 rental apartments.

Bob relished the challenge of complex projects that others thought impossible, including the old Chelsea Post Office, now the Chelsea campus of Bunker Hill Community College and Building 114 in the Charlestown Navy Yard, 30 per cent of which was destroyed by fire prior to Bob's renovating it into 114 high-tech laboratories for biomedical research, a conference space and a waterfront café.

He was a teacher at heart, donating his time to worthy groups as well as serving on the faculty of prestigious educational institutions. He was a lecturer at the Tufts Urban and Environmental Policy Program and the MIT department of city planning, a research associate at the Harvard Business School and an instructor at the Yale department of city planning.

He was president of the Citizen's Housing and Planning Association at the time of his death and past president of Historic Massachusetts, two organizations that are leaders in providing decent, safe and affordable housing and rehabilitating historic structures for contemporary use. He also served as vice chairman of the advisory board of the Massachusetts Community Preservation Act coalition and on the national advisory board of the National Trust for Historic Preservation.

"He was such a great friend and counselor." said Wendy Nicholas, director of the trust's northeast office. "He was always so willing to go anywhere in the 10-state region that we serve to look at endangered historic properties that we were trying to save even though they were usually white elephants! He was a pioneer in taking old buildings and adapting them for new uses."

In 1990, Bob formed Hall Keen management with partners John and Denny Hall to manage a growing portfolio of mixed-income residential properties as well as artist lofts and commercial space. Fittingly, his Harvard Square office was in a building the he rescued from decay and rehabbed into affordable housing.

To relax, he played poker with a group of close friends, fished and flew his single engine airplane on trips between his homes in Maine, Boston, Martha's Vineyard and Key West. In 1990 and 1993, he joined his brother Tom - a professional pilot - and together they flew a small plane across the United States.

"I'd guess Bob's idea of a perfect day would be to fly his plane to a remote fishing site, catch some huge fish, eat them, and then play poker for five hours with his friends while listening to the Red Sox on the radio," said Dick Johnson, who grew up with Bob in Minneapolis and was a lifelong friend.

Bob first came to the Vineyard as my guest in 1960 (we were at Yale together) and he returned often for visits until, in 1998, he purchased a home in Harthaven. From that point on, the Vineyard was a favorite spot. He loved to fish the shoals off Wasque and the grounds on the eastern edge of the Island. He became a savant of smoking bluefish and striped bass.

On the Island, he quickly joined the efforts of affordable housing advocates. He was a founding member of the non-profit Island Affordable Housing Development Corporation in 2001 which was transformed in 2004 into the Island Housing Trust. He played an active role in the formation of the Martha's Vineyard Housing Bank Coalition and also was a board member and former vice president of the Island Affordable Housing Fund.

"Bob was a gentle kind giant whose invaluable knowledge, expertise and contributions to all committees will be so very much missed," said Dale Julier, a board member of the Island Housing Trust.

For the past four years, he had provided pro bono assistance to Bridge Housing Corporation, in their efforts to build Bridge Commons, 30 homes on a 24-acre parcel of land in Tisbury.

Island attorney Marcia Cini, who worked with Bob in the affordable housing and historic preservation trenches for almost 25 years, recalled a moment when she asked him to serve as an expert witness in an appeals trial for Bridge Housing. Bob braved inclement weather to fly his plane to the Island, landing as the fog was gathering in Vineyard Sound. "We asked the judge to let him on first as the weather was closing in; he did a fabulous job for us, and off he flew," she said.

In recognition of Bob's affection for the Penny Lane project in Edgartown, the board of the Island Affordable Housing Fund will rename the project in his honor.

He was an advisor to the National Trust for Historic Preservation, the Massachusetts Housing Finance Agency, the Architectural Conservation Trust, Boston Foundation for Architecture and the Community Preservation Coalition. He was on the board of directors of the Boston Architectural Center, the Citizens' Housing and Planning Association, Historic Massachusetts, Inc, Massachusetts Cultural Council, Massachusetts Special Commission on Historic Preservation and the Mayor's Advisory Panel on Housing in Boston.

He received many awards during his productive life, including preservation awards from the Massachusetts Historical Commission, the Green Seal Award from the Executive Office of Environmental Affairs, an honor award from the New England Regional AIA, a community service award from Citizens Housing and Planning Association, the Paul E. Tsongas Award for Lifetime Achievement in Historic Preservation, a 25th Anniversary Award from the Advisory Council on Historic Preservation and the Copley Society Award for Distinguished Service to the Arts.

He is survived by his brother Thomas Kuehn of Albuquerque, N.M., his sister in law, Cori and his nephew Robert.

Donations in his memory can be made to Bob's Foundation, the Keen Charitable Foundation at 2 University Road, P.O. Box 382589, Cambridge, MA 02238.