In this grand social history Okrent (a popular writer and journalist) illuminates the remarkable cast of characters, the ambitions, and mind-bending complexity in creating the beloved New York City landmark. John D. Rockefeller, his son Nelson, real John R. Todd; and architect Raymond Hood are key players -- along with the likes of Diego Rivera (Okrent retells the familiar story of the murals with aplomb), Gertrude Vanderbilt and (improbably ) Benito Mussolini.  (NYC100, $16.00)