What makes things popular? Why do people talk about certain products and ideas more than others? Why are some stories and rumors more infectious? Wharton marketing professor Jonah Berger has spent the last decade answering these questions. In this new book, Contagious: Why Things Catch On, Berger reveals the secret science behind word-of-mouth and social transmission, and shares the reasons why certain stories get shared, e-mails get forwarded, or videos go viral. He will share how to leverage these concepts to craft contagious content and make your product or idea catch on.