Book excerpt: America's portland cement industry began in the Lehigh Valley. The rich deposit of limestone known as the Jacksonburg Formation arcs through the valley from Berks County, Pennsylvania, to Warren County, New Jersey, and today it still provides the raw material for the Lehigh district's famous high-quality portland cement. Cement from the Lehigh Valley built America's skyscrapers, dams, and highways. The Lehigh Valley Cement Industry documents not only the quarries and cement mills but also the dozens of companies that sprang up to supply and support the industry. The photographs also tell the stories of the people who formed the cement communities—the entrepreneurs, executives, engineers, and immigrants whose legacies live on in the five multinational companies still making cement in the valley.