Eagle-eyed Manhattan pedestrians may spy them high above the street: lush, tree-lined gardens, whose defiant greenery interrupts an urban panorama of concrete and glass.Tourists will never see them up close. Few New Yorkers will but a new book, “Rooftop Gardens: The Terraces, Conservatories and Balconies of New York” satisfies that curiosity with a photographic tour of 28 such exclusive oases. -Photos by Reuters