When Amanda M. Burden's stepfather, William S. Paley, built the vest-pocket park that bears his name on East 53rd Street, he saw to it that the four wide stone steps from the street, each only five inches high, stood as an invitation to enter.

Those steps "are just perfect," Ms. Burden recently recalled her mentor, the urban scholar William H. Whyte, telling her. "It makes you want to skip into that park."

It is that kind of meticulous focus on the details that Ms. Burden inherited from Mr. Paley, the tycoon who built CBS, and is now using to profound effect in subtly reshaping New York through her role as city planning commissioner.