This walking tour with FRIENDS and architectural historian Matt Postal examines the Upper East Side in all its variety, from the finest tree-lined blocks adjoining Central Park to First Avenue.  After viewing a select group of gilded era mansions and clubhouses, we head east, inspecting somewhat humbler carriage houses once occupied by horses, grooms and chauffeurs, unpretentious brownstones built for middle-class residents in the Treadwell Farm Historic District, and ending with the First Avenue Estate, a group of privately-financed model tenements that housed the working poor.