When Henry Luce announced in 1941 that we were living in the “American century,” he believed that the international popularity of American culture made the world favorable to U.S. interests, Northwestern University professor Brian Edwards writes in his book, “After the American Century.”

Now, in the digital 21st century, the American century has been superseded, as American movies, music, video games, and television shows are received, understood and transformed.

Building on a decade of fieldwork in Cairo, Casablanca, and Tehran, Prof.Edwards tracks this shift and maps new routes of cultural exchange that are innovative, accelerated and full of diversions.

Shaped by the digital revolution, these paths are entwined with the growing fragility of American “soft” power. They indicate an era after the American century, in which popular American products and phenomena such as comic books, teen romances, social-networking sites and ways of expressing sexuality are stripped of their associations with the United States and recast in very different forms, Prof. Edwards writes.

Arguing against those who talk about a world in which American culture is merely replicated or appropriated, Prof. Edwards focuses on creative moments of uptake, in which Arabs and Iranians make something unexpected and suggests that these products do more than extend the reach of the original.

“They reflect a world which points to the uncharted worlds far beyond its captured imagination,” said Hamid Dabashi, Hagop Kevorkian Professor of Iranian Studies and Comparative Literature at Columbia University.

Marc Lynch of the University of Iowa wrote, “After the American Century offers a fascinating tour of the appropriation and deployment of American popular culture in a globalized, restless Middle East. From cinema and novels to hip-hop and comic books, this wonderfully written and richly observed book presents novel and exciting readings of familiar cultural forms in new political environments.”

Mr. Edwards is Crown Professor in Middle East Studies and professor of English and comparative literary studies at Northwestern University, where he is also the founding director of the Program in Middle East and North African Studies. He is the author of “Morocco Bound: Disorienting America’s Maghreb, from Casablanca to the Marrakech Express” and a coeditor of “Globalizing American Studies.”