The bar code is now at the core of commerce, transportation, warehousing, manufacturing, and retailing, and its influence has spread to virtually every industry in the industrialized world. When this voluntary product code was first introduced in 1974, it led to the worldwide revolution in supply chain efficiency. To celebrate the twenty-fifth anniversary of this now universally embraced technology, the Smithsonian Institution sponsored a symposium. Gathered together in this volume are the thoughts of eight speakers with hands-on experience concerning the development, diffusion, adoption, and applications of a truly groundbreaking technology. The volume concludes with papers from a panel discussion among those involved in creating the Universal Product Code, the foundation of the bar code.