THE NEWS OF THE sale of Rouse Co. to a Chicago-based mall owner for $12.6 billion is a melancholy reminder of the end of an era. The company, which sprung to life during Lyndon Johnson's Great Society, was a corporate expression of that age's broad-minded idealism. Its founder, James W. Rouse, was a real estate developer; he also wanted to change the world. Utopian, public-spirited and ambitious, Mr. Rouse wasn't so much a trailblazer as a staggeringly successful adopter of new ideas. Among them was the notion that American communities should be self-contained places of "order, beauty [and] reason" that could accommodate the affluent as well as the less privileged and offer them both pleasant places to shop. That was the animating idea behind Columbia, the ultra-planned "new town" that the company built and where it maintains its headquarters. Though Mr. Rouse himself left the company about 25 years ago, in 1979, and died in 1996, the firm he built upheld a tradition of enriching communities in Maryland to this day through its charitable arm, the Rouse Company Foundation.

Rouse Co.'s sale to General Growth Properties Inc., a titan among shopping mall developers, marks the passing of a home-grown institution whose national reach matched its local impact. As the driving force behind Boston's Faneuil Hall Marketplace and Baltimore's Inner Harbor, Rouse lent sex appeal to what had been the dreary topic of urban renewal. Over time, the company became somewhat more conventional, managing more than 150 properties in 22 states and being known more as a developer of chic shopping malls than daring or groundbreaking projects. But it preserved its ties to Maryland both as a major employer in Columbia and as a wellspring of philanthropic giving statewide. The beneficiaries of the Rouse Foundation's largesse have included the Baltimore Museum of Art; the Baltimore Symphony Orchestra; Howard Community College; the New Song Academy, a charter school in Baltimore; and groups helping disabled and disadvantaged people. And the Enterprise Foundation, founded in 1982 by Mr. Rouse and his wife, Patty, has been an important investor in affordable housing for low-income families.

The sale means that some, and possibly many, of the 500 or so employees at Rouse's corporate campus in Columbia will lose their jobs. It comes barely a month after another regional fixture, Riggs Bank, was sold to a company in Pittsburgh. Unlike Riggs, which changed hands in the midst of a scandal of its own making, Rouse Co. sold itself at the peak of its marketability for what seems a very handsome price, the highest ever paid for a real estate investment trust. Also to its credit, the firm's chairman and chief executive, Anthony W. Deering, negotiated a deal whereby General Growth will give the Rouse Foundation a one-time infusion of $20 million. That shot in the arm doesn't disguise the loss to this region. But it should sustain the foundation's presence in Maryland for some years, even as Rouse Co. itself passes from the scene, subsumed into its new parent.