As of the time of this writing, it appears that the host building for this public plaza at 745 Seventh Avenue, the new world headquarters for the investment banking firm of Morgan Stanley Dean Witter & Company, is under construction. If so, that is good news in the long run for public space users. That is because the developer is obligated to complete substantially and open to the public this through-block space, linking West 49th and 50th Streets between Sixth and Seventh Avenues, only when it seeks a temporary certificate of occupancy for up to 75 percent of the new building’s floor area. The developer must fully complete the space prior to issuance of a permanent certificate of occupancy. The only cost to the public is short-term, because it will lose the use of Exxon Park, described in the profile for 1251 Sixth Avenue. Although Exxon Park was not a privately owned public space, in the sense that it was never required by zoning to be open and accessible to the public, it had been open through the generosity of its owner and enjoyed a loyal following. An underground passageway providing subway access is also required.