This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book explores the developing global movements which make use of loud, mobile, acoustic, participatory brass and percussion ensembles to mobilize communities around the world. It explains protest brass bands in post-WWII England, Holland, and Germany in “Jericho’s Harvest: A Short History of Brass Bands as a Voice for Political Opposition in Europe.” The book examines the political strategies of the professional West African Gangbe Brass Band, a band that could be understood as a tangent to HONK!’s expansive global network. It provides an interview with the band’s leader, discussing his internationally comparative reflections on street music, nostalgia, public space, activism, and other topics. The book argues that the School of HONK’s pedagogical approach – based in learning by rote, a tolerance for mistakes, and having fun – constitutes a crucial element of HONK!’s musical activism.