"Contagious" by Jonah Berger explores the science behind why certain ideas, products, and behaviors spread virally while others do not. Berger identifies six key principles that contribute to contagiousness: social currency, triggers, emotion, public, practical value, and stories (STEPPS). Through engaging anecdotes and case studies, Berger illustrates how these principles can be leveraged to create contagious content and drive word-of-mouth marketing. From the surprising success of the "Will it Blend?" campaign to the popularity of viral videos and memes, "Contagious" offers valuable insights into what makes ideas and products inherently shareable.