For over five years, a major cable television company relied on specially-written software to perform transport of its television commercials via satellite to some eighty remote locations. Over 200,000 files were delivered successfully during that time, to just one location, or to more than thirty at once - depending on exactly which locations required any given file. That software was designed by a Chestertonian computer scientist, using the "doctrinal methods of the thirteenth century." Its most critical component, the part which actually managed the file transport, was directly developed from the Principle of Subsidiarity as stated by Pope John Paul II in 1991. The success of that amazing project led to this study of the idea of subsidiarity. Now it's your turn. How will you use subsidiarity in your everyday life? What problems will you solve once you know the principles of subsidiarity?