One day in the fall of 2006, Paul Steiger got a call from Herb and Marion Sandler. It came completely out of the blue. At the time, Steiger was the managing editor of The Wall Street Journal, the paper’s top editorial position, a job he’d held for 15 years. He’d had his share of great moments, including 16 Pulitzer Prizes, and his share of miserable ones, including the murder of Daniel Pearl and the steady drip, drip, drip of cutbacks and layoffs. A year away from The Journal’s mandatory retirement age of 65, Steiger was just beginning to think about what he might do next.

He knew the Sandlers, but not well. “They were people who were interesting and good sources,” he recalled not long ago. “I would have dinner with them once a year or so.” For most of the time Steiger knew them, they had been running a company called Golden West Financial Corporation, which they had built since 1963 from a two-branch savings and loan in Oakland into the second-largest S.&L. in the country.

Steiger also knew them as “civic-minded people who were kind of partial to lefty or progressive causes.” Since the late 1980s, the Sandlers used their wealth to finance a variety of nonprofit organizations, including Human Rights Watch, the American Civil Liberties Union and Acorn, the grass-roots organizers. They helped found the Center for Responsible Lending, where they are among the largest benefactors. They are also among the very few philanthropists in the country who finance basic scientific research, at the University of California at San Francisco. And they have set up nonprofits to conduct research into parasitic diseases and asthma. In 2003, they started the Center for American Progress, which is intended to be a liberal counterweight to the heavyweight policy centers of the right, like the Heritage Foundation and the Cato Institute. So far, the Sandlers have given around $20 million to the center.

All this they have done relatively quietly. Though hardly without ego, the Sandlers nonetheless shun the kind of publicity that accrues to such better-known philanthropists as George Soros and Bill Gates; indeed, the Center for American Progress is sometimes labeled a Soros-financed operation, even though the liberal financier has very little to do with it. And for years, the Sandlers did their philanthropy more or less out of their back pocket, since they were still running Golden West.

But in October 2006, with both of them in their mid-70s, they sold Golden West to Wachovia for $25 billion, reaping $2.4 billion from their stake in the company. They quickly put $1.4 billion into the small foundation they had been using to make their donations, which suddenly made the Sandler Foundation one of the 30 largest in the country. (The Sandlers, who oversee the foundation with three other board members, plan to put the rest of their money into the foundation eventually.) Then they moved into a small suite of offices in downtown San Francisco, hired minimal staff — the Sandlers hate bureaucracy — and got down to the business of giving away their fortune. Starting with, of all things, journalism.

“They told me they were thinking about spending $10 million a year on investigative journalism,” Steiger recalls. The Sandlers didn’t know precisely what they wanted to do, but they knew they wanted to do something big. “They said they were talking to a bunch of people, soliciting ideas,” Steiger says. “What advice would I give them?”

Steiger drew up a proposal for a nonprofit that would employ around 25 reporters and editors and would conduct the kind of ambitious investigations that only a handful of the country’s most prominent news organizations do as a matter of course. Although the Sandlers solicited plenty of other ideas besides Steiger’s, his was the one they loved. They told Steiger that they would finance it, but only if he would run it. After a little soul-searching, Steiger agreed. ProPublica — as it is called — opened its doors in early January and in recent weeks has made its first few hires and named a star-studded advisory board (which includes Jill Abramson, a managing editor of The New York Times). It intends to begin producing investigative articles by the summer and then give its biggest exposés, free, to major news outlets like “60 Minutes.” Although there have been nonprofit investigative efforts in the past, nobody has ever proposed a model quite like this before.

Like most people outside the Bay Area, I’d never heard of the Sandlers before the announcement of ProPublica. But as I quickly came to realize, its creation was a classic Sandler foray. They chose a path — investigative journalism — that few other philanthropists had trod. Rather than give money to someone who approached them, they did the approaching. Rather than finance an organization that already existed, they started their own outfit. They found a star to run it. They seemed almost to relish the thought that they risked failure with this new, unproven model of journalism, though if truth be told, they don’t think they’ll fail. And they gave a lot of money — $30 million for the first three years, with the expectation of continuing that commitment, if not more, for years to come. It’s hard for philanthropists to make a big difference if they’re not willing to spend some serious money, the Sandlers say.