A DOZEN years ago I wrote a column not exactly endorsing Michael Bloomberg for mayor (columnists don’t endorse) but endorsing the idea of Michael Bloomberg. If a guy who built a wildly successful business wants to offer his services to the city, I argued, we shouldn’t let our prejudice against the rich stand in his way. Since then the idea, the C.E.O. as aspiring public steward, has suffered some setbacks (Mitt Romney, for one), but I feel pretty well vindicated by the mayor. As he would be the first to tell you, he will be a very hard act to follow.

In coming weeks I intend to write occasionally about the race to replace Bloomberg — a field of a dozen candidates so uninspiring that a former congressman caught tweeting photos of himself with an erection to women he’d never met is near the lead in opinion polls. But let’s start by taking stock of the incumbent.

For better and occasionally for worse, the rarefied experience Bloomberg brought to the job defined his tenure. Most obviously that began with his billions, which allowed him to self-finance his campaigns and remain largely unbeholden to the city’s clamoring interest groups. Freed from the obligations of retail politics, he could staff his government with top talent rather than people holding political chits. With a few conspicuous exceptions, he hired people of passion and competence. He invited them to experiment, a rare thing in the risk-averse culture of government, but he held them accountable with obsessive attention to metrics. His City Hall, like his eponymous company, was built on the power of information. The great urban contraption that is New York City government has probably never been so well run.

He was not a model of inclusiveness. Whites are only a third of New York’s population, but nonwhites are scarce in Bloomberg’s bullpen. He has lived much of his life in a bubble of privilege, and he has an above-it-all demeanor that contributes to a sense, especially in minority and working-class precincts, that he lacks empathy. He can tell you, with a PowerPoint slide to back him up, that the aggressive police practice of stopping and frisking young men of color in tense neighborhoods has saved lives by keeping guns off the streets. He seems not to appreciate that systematic humiliation corrodes the trust between police and entire communities, and that there might be ways to take the edge off. Bloomberg can be stubborn and tone-deaf. He is easier to admire than to love.