Book excerpt: Due in part to the Lehigh Canal and the Lehigh Valley Railroad, Bethlehem evolved from a tranquil town to a modern industrial city. Built in 1829, the Lehigh Canal passed by the center of Bethlehem. With it brought a steady stream of outsiders who shaped and changed the community. The Lehigh Valley Railroad was established in South Bethlehem in the 1850s, turning the city into a manufacturing center with such new industries as Lehigh Zinc and Bethlehem Steel as well as silk mills. Bethlehem Revisited captures a city in transition, at a time when its streets could barely accommodate the influx of horses, trolleys, automobiles, and pedestrians. Bursting at its seams with people, businesses, and residences, Bethlehem comes alive through this collection of extraordinary postcards.