PHOENIX — Michelle Dodds bounded through a downtown that to the untrained eye seemed to be dominated by gleaming skyscrapers and sports arenas, the kind of shimmering modern structures that lend credence to the stereotype of this being a young city devoid of history.

But Ms. Dodds, the city’s historic preservation officer, knows better.

On this day, she pointed out the old City Hall, where the police interrogation of Ernesto Miranda in 1963 led to the landmark Supreme Court decision requiring officers to inform criminal suspects of their rights. A few blocks away was Barrister Place, where Alfred Hitchcock filmed the opening scene of “Psycho.”

Ms. Dodds could also spot the ghosts of downtown: the buildings that no longer stood and the decrepit spaces long past their glory. Too often, she said, the structures were lost because the case for preservation was unpersuasive, or because too few people knew of their significance.

“You can’t win everything,” said Ms. Dodds, a longtime city employee who, in three years at her current job, has become a student and defender of Phoenix’s history. “You can’t save everything. It’s not possible.”