THE political showdown over a Dubai company's plan to operate terminals at six American ports briefly focused public attention on one of the most significant, yet least noticed, economic developments of the last few decades: the transformation of international shipping.

Just as the computer revolutionized the flow of information, the shipping container revolutionized the flow of goods. As generic as the 1's and 0's of computer code, a container can hold just about anything, from coffee beans to cellphone components. By sharply cutting costs and enhancing reliability, container-based shipping enormously increased the volume of international trade and made complex supply chains possible.

"Low transport costs help make it economically sensible for a factory in China to produce Barbie dolls with Japanese hair, Taiwanese plastics and American colorants, and ship them off to eager girls all over the world," writes Marc Levinson in the new book "The Box: How the Shipping Container Made the World Smaller and the World Economy Bigger" (Princeton University Press).

For consumers, this results in lower prices and more variety. "People now just take it for granted that they have access to an enormous selection of goods from all over the world," Mr. Levinson said in an interview. That selection, he said, "was made possible by this technological change."