Organizations strive to create campaign messages that yield clear, consistent, and resonant interpretations that motivate people to buy their product, support their cause, vote for their candidate, or take active steps to improve or protect their health. However, once these campaigns leave the controlled environments of focus groups, advertising agencies, and stakeholder meetings to circulate through public space, people interpret and use campaigns in ways the designers never intended. Best Laid Plans explains why these instrumental-rational attempts to persuade the public through culture and media often fail. To explain these failures, the book identifies mechanisms that encourage “cultural entropy”: the process through which the intended meanings and uses of cultural objects fracture into alternative meanings, new practices, failed interactions, and blatant disregard. To develop the concept of cultural entropy, the book analyzes HIV/AIDS media campaigns in Accra, Ghana. AIDS organizations in Accra, and throughout the world, seek to control and organize how local communities make sense of the disease. They develop campaigns based on models of “Behavior Change Communication” that purport to use media to change sexual practices. AIDS organizations attempt to control the message by routinizing best practices like evidence-based design, involving opinion leaders in the design process, and getting all organizations behind a single message. Despite their best efforts to persuade the public, campaigns rarely work as intended, disrupted by misinterpretation and misuse. These cultural misfires are not random. Rather, these disruptions are patterned, widespread, and inevitable, indicative of a broader and important-to-understand process of cultural entropy.