The timing of Mr. Lieber’s appointment hardly suggests his task will be simple. The 53-year-old former Lehman Brothers investment banker, who served a year as president of the city’s Economic Development Corporation, is hastening to advance the mayor’s development agenda at the very time that the real estate market is slowing, the city and state are facing billions in revenue gaps, and rising construction costs are putting many approved projects over budget.

With the looming fear that Mr. Bloomberg’s successor after 2009 could scrap or overlook some of the major development projects undertaken but not finished, Mr. Lieber told The Observer his goal is to create a critical mass for the initiatives so that the next mayor would have little choice but to see them to their conclusions.

“A new administration could come in with a different set of objectives than the ones that we’ve worked so hard to establish,” he said. “The interesting thing that I’ve learned in the last year is politics sometimes interferes with what is good governance and good plans and good projects, so you never know who’s doing what in whose interest.”

Mr. Lieber, who was in the private sector for about 25 years, living in Scarsdale for many of them, seems slightly more relaxed than Mr. Doctoroff, who had a reputation for being a forceful, aggressive and frequently successful advocate for the Bloomberg administration.

“Dan is very aggressive, and very effective at making the city’s point of view known, and provides real leadership,” said Robert Yaro, president of the Regional Plan Association, which battled Mr. Doctoroff in the 2005 fight for a West Side stadium. “I think Lieber shares both the willpower and the vision, and in some ways can be even more effective.”

The mayor has lightened the load some for Mr. Lieber, compared with that for Mr. Doctoroff, moving the Department of Buildings, Department of Transportation, Department of Environmental Protection, Taxi and Limousine Commission, and the mayor’s Office of Operations/Long-Term Planning and Sustainability under the control of Deputy Mayor for Operations Edward Skyler, Mr. Bloomberg’s onetime press secretary.

In dealings with at least some elected officials, he has won praise for a more open style, adjusting the plans of previous EDC leadership perceived as relatively obstinate.

In City Council hearings last year, where the chairman of the Economic Development Committee, Thomas White Jr., mispronounced Mr. Lieber’s name multiple times, calling him Mr. LIE-ber (the correct pronunciation is LEE-ber), the then EDC president only responded with a respectful tone, never correcting Mr. White. At a hearing on Willets Point, in Queens, Mr. Lieber invited any disgruntled small-business owner to call him at his office, giving out the phone number.

“All my interactions with Bob Lieber tell me he’s a highly capable, get-the-job-done kind of person,” said Councilman David Yassky, who clashed with the administration over plans to redevelop portions of the Brooklyn waterfront.

AS HE STARTS HIS task of juggling and rushing toward ribbon cuttings, Mr. Lieber faces substantial forces working against him. The strength of the local real estate market, upon which most of Mr. Doctoroff’s initiatives sought leverage, shows cracks in the face of uncertainty on Wall Street. Just Monday, the city’s Independent Budget Office released a report predicting the residential market would slow down substantially in the next two years. The same report predicted a city budget gap of $3.1 billion for the upcoming fiscal year, an amount still less than the projected $4.3 billion budget gap the Spitzer administration is facing statewide.

Construction costs for all projects are on the rise, forcing the city and state to scale back their vision or increase the public contribution. The Jacob K. Javits Convention Center expansion has been scaled back substantially in the name of higher-than-expected costs; the city and state are squabbling over who will cover cost overruns for the 1.5-mile extension of the No. 7 subway line; and the state is soon to start construction on Brooklyn Bridge Park while not having a revenue source to ensure its completion given the increase in costs.

Mr. Lieber will also face an executive in Albany that has a slightly different political schedule—Governor Spitzer faces reelection in 2010—and a tense relationship with the Legislature, especially when compared with the relatively seamless bond between the Bloomberg administration and City Council Speaker Christine Quinn—though even the Council could become less cooperative as the 2009 election season nears.

And, as is so often the case with development, communities oppose most any project that would alter the character of a neighborhood.

Those projects in their early stages seem the most vulnerable. At Willets Point, the proposed redevelopment of a 60-acre automotive repair district by Shea Stadium has met resistance from business and landowners who are being threatened with eminent domain.

And at Coney Island, where the city wants to dramatically transform the amusement hub into a year-round destination, local elected officials, who are often highly influential in the needed approvals from the Legislature and City Council, have responded aggressively, charging that the Bloomberg administration is shoving a flawed plan down their throats.

Mr. Lieber, citing extensive community outreach in the planning stages, seems to see such resistance from elected officials—State Senator Carl Kruger bussed in 500 people to oppose the city at a community meeting on the plan—as lacking in substantive criticism.

“I haven’t heard any true objections about what our plan is ultimately for Coney Island. The rhetoric that exists around the different parts of it I would attribute to politics, and there’s a whole bunch of factors included in that,” he said.

For Coney Island and almost every other project on his plate (a redevelopment of Governors Island; the construction of new parkland along the Brooklyn waterfront; the redevelopment of Pennsylvania Station; the expansion of the Javits Center; and the creation of 5,000 new units of moderate income housing in Long Island City, to name a few), Mr. Lieber said he sees a constant theme of what his work will entail, for which he offered an analogy.

“At 211 degrees, water doesn’t do anything; it just sits in the pot. At 212 degrees, that’s when you actually get something to happen,” Mr. Lieber said. “Our job is to get these projects to the boiling point, if you will, so we can actually make things happen, and not just say, ‘Jeez, we really tried hard, did a lot of work, worked really, really hard,’ and not have anything to show for it.”