Americans once eyed the latest Paris fashions in the hope of being chic; now fashion cool is more likely to be found on the frames of kids from LA and London. In corporate boardrooms, managers and entrepreneurs seek to adopt new ideas from competitors. Government programs aim to combat assorted social ills spread within and between nations. Musical idioms flow between jazz, dance music, and symphony halls. All this commotion about the new, the chic, the cool, and the best prompt some ideas to spread, some ideas to be reinvented through contact with other ideas, and some ideas to languish or die.''This special issue of THE ANNALS, The Social Diffusion of Ideas and Things, devotes its attention to the hows and whys of the diffusion of ideas and things between people, organizations, and cultures. In this issue, discussion if diffusion covers a diverse range of topics:''''''* Fashionable clothing''* Community outreach''+ Industrial pollution''+ Political activism''+ Morality policy''+ Tobacco regulation''+ Jazz music''+ Diffusion theory''Studies in diffusion provide insights into social processes of innovation and communication of the transmission and adoption of new ideas, new practices, and new technologies. This special issue familiarizes readers with basic hypotheses on diffusion that guide contemporary scholarship and is a useful tool to any social scientist.